My biggest issue was with the 3.12 -> 3.13 transition, when musl got upgraded to 1.2 and with it "musl 1.2 uses new time64-compatible system calls". This broke so many things for me without me knowing, like nginx having as the datetime in the logs the unix epoch. All continued to work, but everything related to timestamps was completely messed up, on 32 bit OS due to running on Raspberry Pis.
This was the moment where I decided to stick to debian-slim, and only very specific containers will continue running on Alpine. Before that it was my default container OS.
Also there is no reliability in packages getting updated, sometimes they just disappear in the next version. But these things are rare occurrences, which only are then nerve wracking when you are confronted with them. For 90% of the cases Alpine is one of the most awesome container OSs.