iDRAC.SNMP.AgentCommunity string fall back to ismuser

Hello Community, 

I have a problem, I have a personal iDRAC.SNMP.AgentCommunity string set on my rack host, and somehow the string fallback to the default ismuser and I have no logs or anything where I can found why this is happen.

PowerEdge R630 - BIOS: 2.7.1

IDRAC: 2.50.50.50

OS: Ubuntu 18.04.6 LTS

Did someone meet this problem?