We've had 2 LCPs returned to our shop in the past week, both with the magazines falling out when shooting. My first guess was someone squeezing the gun so tight they were hitting the mag release.
However, upon inspecting the guns the magazine catches were worn. I think it's happening from a customer putting the mag in and "slamming" it home with a slap on the bottom.
I'd recommend a little TLC when inserting the magazine.