Hello
Couple days ago my monitoring system detected problem with stack. Before wasn't did any changes on switches.
Could you please tell me what can be the reason?

  20:39:08: %STKUNIT0-M:CP %CHMGR-5-MODULE_INSERTED: 10GBASE-T module has been inserted in stack-unit 1 optional slot 0
  20:39:08: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/16
  20:39:08: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/8
  20:39:08: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/7
  20:39:07: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/26
  20:39:07: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/25
  20:39:07: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/18
  20:39:07: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/17
  20:39:06: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/15
  20:39:06: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_PFC_PARAMETERS_MATCH: PFC Parameters MATCH on interface: Te 1/10 
  20:39:06: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_ETS_PARAMETERS_MATCH: ETS Parameters MATCH on interface: Te 1/10 
  20:39:06: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/10
  20:39:06: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/9
  20:39:05: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/2
  20:39:05: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Te 1/1
  20:39:05: %MXL-10/40GbE:1 %POLLMGR-2-MODULE_POWER_STATE: Module 0 in unit 1 changed to POWER GOOD state
  20:39:05: %MXL-10/40GbE:1 %IFAGT-5-INSERT_OPTICS_QSFP: Optics QSFP inserted in slot 1 port 37
  20:39:05: %MXL-10/40GbE:1 %IFAGT-5-UNSUP_OPTICS: Non-qualified optics in slot 1 port 33
  20:39:04: %MXL-10/40GbE:1 %IFAGT-5-STACK_PORT_LINK_UP: Changed stack port state to up: 1/37
  20:39:04: %MXL-10/40GbE:1 %IFAGT-5-STACK_PORT_LINK_UP: Changed stack port state to up: 1/33
  20:38:58: %STKUNIT0-M:CP %CHMGR-5-STACKUNIT_UP: stack-unit 1 is up
  20:38:53: %MXL-10/40GbE:1 %LCMGR-5-IOM_STATE: Switch status of stack-unit 1 is set to Good
  20:38:53: %STKUNIT0-M:CP %CHMGR-5-CHECKIN: Checkin from stack-unit 1 (type MXL-10/40GbE, 56 ports)
  20:38:49: %STKUNIT0-M:CP %IRC-6-IRC_COMMUP: Link to peer Stack-unit is up
  20:38:40: %MXL-10/40GbE:0 %F10STKMGR-4-CHASSIS_MAC_OWNER_IN: Owner of MAC(F8:B1:56:20:65:10) is back in the stack.
  20:38:40: %STKUNIT0-M:CP %CHMGR-5-STACKUNIT_DETECTED: stack-unit 1 present
  20:38:39: %STKUNIT0-M:CP %POLLMGR-2-ALT_STACKUNIT_STATE: Alternate Stack-unit is present
  20:38:29: %MXL-10/40GbE:0 %IFAGT-5-STACK_PORT_LINK_UP: Changed stack port state to up: 0/37
  20:38:28: %MXL-10/40GbE:0 %IFAGT-5-STACK_PORT_LINK_UP: Changed stack port state to up: 0/33
  20:37:24: %STKUNIT0-M:CP %CHMGR-2-SYSTEM_READY: System ready
  20:37:24: %MXL-10/40GbE:0 %LCMGR-5-IOM_STATE: Switch status of stack-unit 0 is set to Good
  20:37:02: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_PFC_PARAMETERS_MATCH: PFC Parameters MATCH on interface: Te 0/15 
  20:37:02: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_ETS_PARAMETERS_MATCH: ETS Parameters MATCH on interface: Te 0/15 
  20:37:01: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_PFC_PARAMETERS_MATCH: PFC Parameters MATCH on interface: Te 0/17 
  20:37:01: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_ETS_PARAMETERS_MATCH: ETS Parameters MATCH on interface: Te 0/17 
  20:37:01: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_PFC_PARAMETERS_MATCH: PFC Parameters MATCH on interface: Te 0/25 
  20:37:01: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_ETS_PARAMETERS_MATCH: ETS Parameters MATCH on interface: Te 0/25 
  20:37:00: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_PFC_PARAMETERS_MATCH: PFC Parameters MATCH on interface: Te 0/18 
  20:37:00: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_ETS_PARAMETERS_MATCH: ETS Parameters MATCH on interface: Te 0/18 
  20:37:00: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_PFC_PARAMETERS_MATCH: PFC Parameters MATCH on interface: Te 0/10 
  20:37:00: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_ETS_PARAMETERS_MATCH: ETS Parameters MATCH on interface: Te 0/10 
  20:37:00: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_PFC_PARAMETERS_MATCH: PFC Parameters MATCH on interface: Te 0/9 
  20:36:59: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_ETS_PARAMETERS_MATCH: ETS Parameters MATCH on interface: Te 0/9 
  20:36:59: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_PFC_PARAMETERS_MATCH: PFC Parameters MATCH on interface: Te 0/1 
  20:36:59: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_ETS_PARAMETERS_MATCH: ETS Parameters MATCH on interface: Te 0/1 
  20:36:59: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_PFC_PARAMETERS_MATCH: PFC Parameters MATCH on interface: Te 0/2 
  20:36:58: %STKUNIT0-M:CP %DIFFSERV-5-DSM_DCBX_ETS_PARAMETERS_MATCH: ETS Parameters MATCH on interface: Te 0/2 
  20:36:58: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Po 30
  20:36:58: %STKUNIT0-M:CP %LACP-5-PORT-GROUPED: PortChannel-030-Grouped: Interface Te 0/17 joined port-channel 30.
  20:36:58: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Po 31
  20:36:58: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Po 25
  20:36:57: %STKUNIT0-M:CP %LACP-5-PORT-GROUPED: PortChannel-031-Grouped: Interface Te 0/9 joined port-channel 31.
  20:36:57: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Po 22
  20:36:57: %STKUNIT0-M:CP %LACP-5-PORT-GROUPED: PortChannel-025-Grouped: Interface Te 0/25 joined port-channel 25.
  20:36:57: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Po 23
  20:36:56: %STKUNIT0-M:CP %LACP-5-PORT-GROUPED: PortChannel-022-Grouped: Interface Te 0/18 joined port-channel 22.
  20:36:56: %STKUNIT0-M:CP %LACP-5-PORT-GROUPED: PortChannel-023-Grouped: Interface Te 0/10 joined port-channel 23.
  20:36:56: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Po 15
  20:36:56: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Po 21
  20:36:56: %STKUNIT0-M:CP %LACP-5-PORT-GROUPED: PortChannel-015-Grouped: Interface Te 0/15 joined port-channel 15.
  20:36:55: %STKUNIT0-M:CP %LACP-5-PORT-GROUPED: PortChannel-021-Grouped: Interface Te 0/2 joined port-channel 21.
  20:36:55: %STKUNIT0-M:CP %LACP-5-PORT-GROUPED: PortChannel-002-Grouped: Interface Te 0/44 joined port-channel 2.
  20:36:55: %STKUNIT0-M:CP %LACP-5-PORT-GROUPED: PortChannel-002-Grouped: Interface Te 0/43 joined port-channel 2.
  20:36:55: %STKUNIT0-M:CP %IFMGR-5-OSTATE_UP: Changed interface state to up: Po 2
  20:36:55: %STKUNIT0-M:CP %SEC-3-AUTHENTICATION_FAILURE: Authentication failure on console for method "local" user "" 
  20:36:54: %STKUNIT0-M:CP %IFMGR-1-DEL_PORT: Removed port: Te 1/1-32,41-44,49-56, 
  20:36:54: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/44
  20:36:54: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/43
  20:36:54: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/26
  20:36:54: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/25
  20:36:53: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/18
  20:36:53: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/17
  20:36:53: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/16
  20:36:53: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/15
  20:36:52: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/10
  20:36:52: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/9
  20:36:52: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/8
  20:36:52: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/7
  20:36:52: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/2
  20:36:51: %STKUNIT0-M:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Te 1/1
  20:36:51: %STKUNIT0-M:CP %IFMGR-5-ASTATE_DN: Changed interface Admin state to down: Ma 0/0
  20:36:51: %STKUNIT0-M:CP %CHMGR-2-STACKUNIT_DOWN: stack-unit 1 down - card removed
  20:36:51: %STKUNIT0-M:CP %RAM-5-STACKUNIT_STATE: Stack-unit 0 is in Active State.
  20:36:50: %STKUNIT0-M:CP %RAM-5-HOT_FAILOVER: Stack-unit Failover Completed.
  20:36:50: %STKUNIT0-S:CP %POLLMGR-2-ALT_STACKUNIT_STATE: Alternate Stack-unit is not present
  20:36:49: %STKUNIT0-S:CP %RAM-6-ELECTION_ROLE: Stack-unit 0 is transitioning to Management Stack-unit.
  20:36:49: %STKUNIT0-S:CP %RAM-6-FAILOVER_REQ: Stack-unit failover request from active peer: Auto failover on failure
  20:36:47: %MXL-10/40GbE:1 %KERN-2-INT: registers:
  20:36:47: %MXL-10/40GbE:1 %KERN-2-INT: trap: cpu0, pid 682(ofmgr): sig 11: cause=0x8 epc=0x2dcc1b68 va=0x2dcc1b68 (asid 4)
  20:36:46: %MXL-10/40GbE:1 %KERN-2-INT: pid 639 (Dhcpv6Rly): trap: bad insn @ 0x10018138 cause 0x2c insn 0xbfb60040 code 1



#sho system brief 

Stack MAC                  : f8:b1:56:20:65:10
Reload-Type                : normal-reload [Next boot : normal-reload]

--  Stack Info  --
Unit  UnitType  Status    ReqTyp          CurTyp          Version     Ports
------------------------------------------------------------------------------------
0   Management   online  MXL-10/40GbE    MXL-10/40GbE    9.9(0.0)    56     
1   Standby      online  MXL-10/40GbE    MXL-10/40GbE    9.9(0.0)    56     
2   Member       not present                    
3   Member       not present                    
4   Member       not present                    
5   Member       not present