Bitwarden locks immediately after unlocking

I have Bitwarden installed on my iPhone SE. iOS 18.3
I install the Gmail app. I login to gmail on the app. Underneath the username field, my iPhone suggests “Passwords” for that username. I click on that suggestion (not in the Gmail app). Bitwarden opens but I must first unlock. I unlock with my master pwd and click copy username. Back to the Gmail app, paste my username, now Gmail asks for my pwd. Again, my iPhone suggests “Passwords for [Gmail account]” and I click on it. … but Bitwarden is now locked and asks me again for my master pwd.
This happens every time, not just with gmail app but every other app. My workaround is to FIRST open the Bitwarden app with master pwd, copy username, switch back to app, paste, switch back to Bitwarden, copy pwd, switch back to app, paste.
In Bitwarden settings > Account security, “Unlock Options” is “Unlock with PIN code (ON)”, Session Timeout = 1 hour. Session Timeout action = “Lock”.
Version 2025.1.3 (1884)
Is this supposed to happen, or am I doing something wrong?