I have this is in the console when it happens:

Notes:

• it's happening on a subwiki, and the extension is also installed on the main wiki.
• I think the version of the scripting documentation extension on the main wiki is not the good one (it's 1.4), but it works on the main wiki
• contrary to my previous comment, it's probably happening also after a restart, I can still reproduce it and the server probably got restarted in the mean time.