All of the random holidays were working fine for me prior to the November patch, and now none of them are. Like others who have posted here, I see them on the calendar but they disappear at 6 am on the day they are scheduled to occur. No holiday interactions, nothing. I especially loved the Talk Like A Pirate Day. I would not say they were ever an essential part of my game-play, but I did enjoy the variety they brought. The four seasonal holidays and any custom holidays I have added still work fine, so I'm pretty happy about that.
The programmers at EA Maxis must have put a lot of time into creating these random holidays in the first place, so I really hope they can come up with a fix for this bug soon.
I've tested this on new, no-mod + cc-free game saves and even tried running the game repair option through Origin. The game repair did not fix it. If anyone has any suggestions on how to fix this, I'd be happy to give them a try. If it's already posted somewhere on this site, please reply with a link. Thanks!