This started when Blast to the Past ended.
First, my sims aren't getting holidays off. Every holiday they're at work and lose out on time to participate in full on the busier to do list ones like Winterfest. A few of them can't even call out for the day off.
Second, some holidays are missing from the Calendar that I didn't remove. Only ever altered the calendar to remove prank day. Summer is empty, Spring just has Love day, and most importantly Spooky day is missing.
Tried repairing multiple times, started a new save to find the same problem at the start without altering the calendar and never have I used mods on the game.