Yes, this server has been basically unchanged hardware-wise since built. The only change I made recently was to upgrade from 16GB of RAM to 32GB, but this same behavior occurred with both sets of RAM. I host 2 Minecraft servers, a calibre-web instance, homebridge, and more... so there are many things that could be causing this from a container / services perspective.
I'm trying to think of weak links here hardware-wise and I feel it's worth mentioning I had my cache pool (single Samsung 970 EVO 250GB) become unmountable last month which I posted about here. I ended up having to repair the filesystem which allowed me to copy over the entire contents of the cache drive to the array, format the SSD, and then copy the contents back. Everything has worked the same since that. The SMART data for this SSD doesn't seem bad to me but I could be wrong...