It looks like a new bug of WKOF, which Jitai uses. (See here and here)
EDIT: I just noticed that this only applies to Lessons, and not Reviews. Can you tell me what browser and OS your are using so that the settings menu doesn’t appear?
tbh the auto-update (TamperMonkey, Safari) never worked for me for any script. But if I click on “Check for userscript updates” in Tampermonkey then it fetches all new updates of all scripts, even from GitHub.