Bitwarden ask the master pasword every few days (or week?) instead of the pin

(I’m using the destktop app on my PC with edge chromium)
Bitewarden should unlock with pin at brownser restart. It does that usually, but after few days or week, it requires the master password which is annoying (eventhough nothing change: I did not log out from birwarden neither from edge).
Any idea what could go wrong? (I triple checked the settings with a friend, it should work). Something seems to logout bitwarden.