It does look like some of it is a cache problem. There were some warnings about goofy things happening on the phpBB upgrade groups, but I didn't have a problem on the ones I upgraded.
I purged the cache on Firefox, and it allowed most of the stuff here to be visible again, but there are still missing pieces. Oddly enough, I'd never used chrome to come here, and it had the same problems.
Switching to a different theme will probably fix it for everyone at once, as the cache won't be the same. I'm not the admin here, so i'm mostly blowing smoke.
So, for a quick fix, purge your browser cache.