I absolutely hate problems coming up randomly or without an identified...
... which might cause 20s caps in the logs, too ?
RAM ?
I've searched the samba bugzilla for "INTERNAL ERROR Signal 11"
As I'm not a developer I can't judge if the newest report named "Regression: Samba 4.15.2 on macOS ..." (and of cause the patch => comment #3) makes sense/could help (in case if it would be able to be backported)
but maybe the "Client specific logging" settings I found here:
1. https://wiki.samba.org/index.php/Client_specific_logging
- it seems it's something more then just "log level 10" -
and
2. against the log cap and because the error occurs randomly to set in the LE configuration Tool => System => Logging (on the right) => "Use persistent Logs" (systemd log survives reboots) in combination with the boot parameter HiassofT suggested (if not already set)
- I couldn't exactly get in which log your 20s gap occured (samba log's, systemd log or both) -
happy bug hunting