Gateway log full of write errors

I have a project (v7.9.10) in production for one month now.
Every once in a while the gateway log is filled with 100’s of these errors and warnings:

I can’t find any pattern when (or why) those errors happen.
The gateway is running on Windows 2016 Server VM with a connection to the Siemens S7-1515 PLC.
It looks like the gateway is lost connection to the PLC, but if you look at the screens on the client, there’s no indication of that. All statutes are showing OK.
But the hand operations (jog) aren’t working. Looks like all tag writes to the PLC are not working.
If you wait for a few minutes then everything is back to normal. Until after a few hours or a few days it happens again.
If anybody has some thoughts on that, please, share them.
Here are the system log dump and thread dump: (1.1 MB)
thread_dump.txt (103.8 KB)