if it's gunk keeping it from popping back out you can clean the slot with the corner of a post it note. you can also run it under warm water.

I have the same issue. My watch is the same age, more or less.

I clean my watch, protector, and band ends with rubbing alcohol once a month. I remove the band and clean the slot that the band slides in.

I will try cleaning under the crown with a slip of paper.