I just upgraded to Moodle 3.8 (build 20191118). Now I (as the admin) and probably other users can no longer access my profile - when clicking on the link next to my name at the top right, nothing happens. (Well, a blue box is drawn around the name and triangle, but no menu pops up). The same applies when clicking on the "burger menu" - nothing happens. Also, grading a submission does not seem to work (loads endlessly).
I tested this on my main computer (macOS, Safari + Firefox + Chrome) and Windows 10 (in a VM, Firefox + Edge), so I assume that this is a general issue. I have no idea what the reason might be, and debugging also does not show anything helpful.
It does show in the server logs that a file is missing (as below), and hints on what can be done to fix this would also be appreciated (the file actually exists in the top directory).
2019/11/17 13:03:59 [error] 10005#10005: *28511404 FastCGI sent in stderr: "PHP message: Default exception handler: File not found. Debug:
Error code: filenotfound
* line 494 of /lib/setuplib.php: moodle_exception thrown
* line 2074 of /lib/filelib.php: call to print_error()
* line 96 of /admin/lib.php: call to send_file_not_found()
* line 5009 of /lib/filelib.php: call to core_admin_pluginfile()
* line 44 of /pluginfile.php: call to file_pluginfile()" while reading response header from upstream, client: 188.8.131.52, server: moodle.informatik.tu-darmstadt.de, request: "GET /pluginfile.php/1/core_admin/logo/0x200/1573991495https%3A//moodle[...]/apple-touch-icon.png HTTP/1.1", upstream: "fastcgi://unix:/run/php/php7.3-fpm.sock:", host: "moodle.[...]", referrer: "https://moodle.[...]/login/index.php"