Wireguard on RT6600ax stops occasionally

I've updated the binary by using the script.
The wireguard connection is working for hours. But after a while (a day or so) I cannot connect anymore. ps | grep wire show's that no process is running. After starting it again with /usr/local/etc/rc.d/wireguard.sh start it's running and working again.

The router is not rebooted (running for weeks).

What can I try to find the problem?

edit: I think after a ssh logoff the process stops working