@dpnguyen
Hmmm… Weird.
In my test (with my calendars), I cannot find anything wrong.
Try self-testing more.
Remove all other modules except CX2 from config. (You can backup your original config.js), Then try again.
You have two month views on a screen. Usually, screen is not so huge to hold multi month views. Is there any special reason? Anyway try with just one month view.
Investigate the Front-end Log and Backend-log. Is there any suspicious message in both? Especially in scanning result in back log, how it shows?
(EXAMPLE)
[29.08.2023 08:58.32.610] [LOG] [CALEXT2] calendar:Gracie >> Scanning start with interval:60000
[29.08.2023 08:58.32.843] [LOG] [CALEXT2] calendar:Gracie >> Scanned: 18, Selected: 18
[29.08.2023 08:58.33.977] [LOG] [CALEXT2] calendar:General >> Scanning start with interval:60000
[29.08.2023 08:58.34.360] [LOG] [CALEXT2] calendar:General >> Scanned: 23, Selected: 23
[29.08.2023 08:58.34.662] [LOG] [CALEXT2] calendar:Nora >> Scanning start with interval:60000
[29.08.2023 08:58.35.435] [LOG] [CALEXT2] calendar:Nora >> Scanned: 96, Selected: 96
Were the scanned/selected results changed in close cycles? (You can test it with short scanInterval of calendar)
Without original ical data and environment, I cannot reproduce your issue. Could you send me the original config.js and custom.css privately? (eouia0819@gmail.com) I’ll drop your ical after investigation.