Seasons: Calendar reset and unable to add new holidays

Product: The Sims 4
Platform:PC
Which language are you playing the game in? English
How often does the bug occur? Every time (100%)
What is your current game version number? 1.63.136.1010
What expansions, game packs, and stuff packs do you have installed? Cats and Dogs, City Living, Get Together, Get to Work, Seasons, Parenthood, Dine Out, Spa Day, Jungle Adventure, Movie Hangout Stuff
Steps: How can we find the bug ourselves? Go into the Calendar view and try to create a new event
What happens when the bug occurs? Spring skipped back to the beginning instead of going into summer, all holidays have been shifted by a week, I'm unable to add new holidays.
What do you expect to see? My season back to summer, holidays displaying in the right season, and being able to add holidays.
Have you installed any customization with the game, e.g. Custom Content or Mods? Not now. I've removed them.
Did this issue appear after a specific patch or change you made to your system? Neutral/Not Sure 

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Hello!

I logged onto my game just on the last day of spring, and it should have changed season overnight, but the following happened:

- My game skipped a season, spring was ending and went back to the first day of spring again. As in, my game did not reset: my Sims's progress had saved, nobody "went back in time", but the calendar reset.
- When opening the calendar after the first day of "new spring", all seasons had been shifted by one week: spring contained the holidays of both spring and summer (sometimes two on the same day), summer had autumn holidays, autumn had the winter holidays, and winter was empty.
- I tried creating test holidays, but not all of them were successfully added. It seems I was only able to add holidays to days the game recognised as empty: the whole winter week was, technically, empty, but if I tried adding an event to the third day of the week (which is where I put Winterfest) or the last day (New Year's), it didn't add anything. However, I could add an event to the second day, which didn't have a holiday on it before the bug occurred.

I did notice this after installing the Meaningful Stories mod on Saturday afternoon, 27/06/2020, but it could just be a coincidence, since I've now removed my mods and tested. I've also already deleted the localthumbcache.package and repaired the game, but the problem still occurs.

I've linked my saves, config log, LE files, and also my script mod folders

Thanks a ton for looking into this!

(Removed link to mod and removed folder link. No mod links on the forum) - Atic