I had an FA in D1 on LAX-DCA tell me last year that DL has about 6-7 blown slides a month. The FA's get dinged hard if they're responsible. She didn't elaborate, but apparently coming out of the pandemic they've had an uptick in slide deployments.

For the question above regarding where the slides are located, on most exit doors (ie. L1/L2, etc) the slides are at the base of the door. When you hear the FA's announce dis-arm and crosscheck, that is the process of them disarming the slides. If an FA doesn't disarm (place a pin correctly, in most circumstances) and then door is opened, the slide will deploy. For over wing exits, the slides are in the side of the fuselage or top of the wing. (See this video of an A320 slide deploying: ) Here's a 737 Max slide deployment: