my automatic updates always failed and I had to push the files manually. It crashes when copying files. Now is the first time I checked the log what actually happens.
I am using debian 10 with nginx. Log is attached.
It shows something that should only happen if you had a mix of old and new files.
It shows that webtrees is trying to generate the menus - which it would not normally do on a POST (update) request.
Although it might happen if there was an error, and webtrees was trying to generate a friendly error page.
So, my interpretation of this error is that
a) an error happened while copying files.
b) webtrees tried to display an error message, but failed because it had a mix of old/new files.