This is the most stupidest noobie question and I apologize.
I've been using AE 2015 for a little bit now, trying out Duik and other puppeting tools. I was doing great until today, when suddenly, ctrl-z doesn't show up immediately. It isn't until I scrub the timeline that I see what changes have been made. I feel like this wasn't the case just a day or so ago (I was making things so easily but now with this I keep tripping up, undoing more time than I mean to and having to reanimate things). I hate having to stop to scrub the timeline every fracking time I undo something, which is constantly. Did I accidentally click a setting or something?
Purge your cache.