I had some issue that after hours run, lost communication to PLC and not being able to recover back.
I ran wireshark and debug option 2, noticed libplctag sent 4003 byte of payload then no response from PLC when into reconnection.
it seems payload count was wrong and overwrite a byte to hostIP address, so it went into reconnection loop due to incorrect ip address.

maybe it should account for size of sequence count?

I'm using 2.6.6 on windows 11 and CompactLogix 5069-L306ER

stderr.log