Intermitent LAN availability

[rebuilder]

Running 23.1.5_4 on a pcengines apu4d4. I have a problem with the lan connections
disconnecting and reconnecting without a pattern. Don't think the problem is hardware since I have two
apu4d4 the second one in hot spare mode and switching between hardware doesn't seem to help.

Like to know what what logs and diagnostics I should be using to establish reasons for this behavior.
I have not had the problem in previous opnsense versions