Update

My advice for playing the Rewards Events is to pull out your Mods folder and use a separate save for them. You'll be less likely to run into issues. No creator is going to update their content so it works for a temporary event.

If you mean regular gameplay, not the Rewards Event, you might just have individual items that are broken somehow. Check Broken/Updated Mods & CC 

I now seem to have the same problem. And every maker for the mods in my game have said their mods are updated for this patch or are good for this patch. But with the mods in, no u/I and no BB mode. Why can't they make this something to opt out of. 

Well, no mods until this sucky event is over. Thanks again EA!

Sounds like your mods aren't actually on the current versions or like you still have an old version as well as a new one in of something. Start at Broken/Updated Mods & CC 

You are correct. It is a mod, but according to the creators site, it is updated for the latest patch. And I am sure of which mid, as I check them 1 by 1 to be sure. So I guess until another update of the mod comes out, I will have no choice but to lose it from my game. It turns out the same thing occurred when leaving CAS and when traveling from the lot to another. Bummer.

To anyone else experiencing this, it is the U/I Cheat Extension. It may say updated on his site, but it will not play in MY game anymore. With all of my mods back in my game but this one, my game is fine. Put this one back in, everything is borked. 

The updated version is fine and doesn't conflict with the Rewards Event at all. (I was just playing this yesterday.) Sounds like you have something in your mods folder that conflicts with it. That new Arnie Cheatsmaster mod is an obvious possibility - it conflicts with a lot of other mods. 

My game is still broken even without any mods. I have also uninstalled and reinstalled the game and it is still broken.

It's not breaking that either. I guarantee you - I use this, and I run the Broken/Updated Mods & CC list. It sounds to me like you have an older version in your game as well as the new one, or like you're actually one version behind. Version 1.45 released December 3 at https://www.patreon.com/posts/ui-cheats-v1-45-26240068 does not cause any UI glitching at any point in the game.

Broken how? 

Build mode is a blue screen, in gameplay every action/menu option is double and if I for example click a sim and choose friendly interaction and small talk ect. , the previous action will stay on the screen, as in overlaying eachother. Besides that it is slow and freezes and simply put, un-playeable. I have tried everything and it just does not work.