Oh I'm really sorry to hear that. That must be a problem arising from switching to event pages. I'll look into it right away and hopefully fix it soon. Thank you for letting me know!

Update 2023-12-06: I've fixed the bug and submitted a new version (1.17) to the add-ons store. It will appear as soon as Mozilla finishes reviewing it.

Update 2023-12-11: The updated version has been approved and this should now be fixed. Thank you for reporting the issue and sorry for the inconvenience.