With everything you stated I would confirm if the server is up to date, specifically the BIOS and iDrac. The reason being is that the issue doesn't appear on the older OS. What is the current version for both the BIOS and iDrac on the server? Also what is the specific errors you are seeing, I assume one is the SWC0700 error, are you seeing that and anything else?
Let me know.
Hi Chris, The R420 BIOS is FW package: 20.12.0-0004 CPLD version:104 Warning! iDRAC initialization error. Continuing to boot may yield unexpected power loss due to unkown power inventory and various fertures lost such as Remote Access, Active Power Management, Thermal Management, Inventory, LCD, or SYstem Error Reporting. Management Engine Mode: Active Management Engine Firmware Version: 0002:0001 Patch: 0005 Build: 006D SWC0700 error raised. My R420 service tag is <Service tag removed>. Pls let me know if more information. Thanks so much.
The version given for the BIOS is in fact the idrac version, and is a few updates back. Would you update the two to current and verify if the issue persists?