First of all, I wasn't "worried" about anything. I saw a strange, unexplained anomalie and asked in case there was a simple explanation that I was unaware of. Curiosity and annoyance were my primary drivers.
I ended up seeing the 'limit' go up and down from 180, down to 120, back up to 220, down again to 120, and finally up to 220 whereupon I got in and forgot all about it. This happened in a time space of roughly 15 minutes. It was just very strange bouncing around like that, to no seeming purpose.