I had the opposite experience- mine went up.
I've been bouncing between an 8 point spread forever. During a recent home improvement project, I decided to take advantage of a cash back credit card offer. Over the course of the application process, charging about $2000 to it, and then immediately paying it off, my score went up 10 points over its previous high. That was a couple months ago and now I'm back bouncing between that same 8 point spread.