SMB seems to be crashing or otherwise failing after some time

I'm having a recurring issue with OMV5 where my SMB shares stop working after some time and I have to reboot OMV to get them to work again. I'm still able to access the web interface and everything looks and functions OK there, low memory and cpu use is reported. Stopping the SMB daemon times out on reboot when this occurs and the drives fail to cleanly unmount.

I have 3 machines connected to these shares, one Win10, and two Debain Buster servers, I have noticed the average load of the Debian servers goes through the roof when they loose access.

When this happens there is some kernel output on the console that might point someone more knowledgeable in the right direction to give me some help.

I've also noticed that I'm getting stale file handles on some of my client mounts, and this is what I'm seeing on reboot of one of them, the server was up when this was rebooted. Oddly, the share in the last line was not one of the ones with a stale file handle.

This issue was not present over the last year with OMV4

Whatever is happening seems to be happening at, or around, 00:00 every day. The timestamps show that the server was up for ~17 hours 40 min before this happened which correlates to the spike in processes just after midnight in the graph below. But, as you can see, the system otherwise looks healthy.

No, I ended up reinstalling at some point and the issue has not returned.