After Telegram auto-locks in the background, unlocking it with a fingerprint while a mini app is open can leave a full-screen transparent passcode dialog window active. The interface remains visible but no longer responds to touches and cannot be closed normally.
The same issue can occur with the attach menu open in a regular chat; in that case, the interface may also remain visibly zoomed to 1.25x.
Unlocking with the PIN does not reproduce the issue, and it does not occur when the passcode is disabled. The issue is caused by the PasscodeViewDialog window remaining on screen after the fingerprint unlock and consuming touch events.
Note: A fix is available in PR #2031. The fix was tested against Telegram Android 12.10.1 built from source.
Steps to reproduce
Enable Settings > Privacy and Security > Passcode, set auto-lock, and enable fingerprint unlocking.
Open any mini app, including the official Wallet mini app.
Background Telegram for two minutes so that it auto-locks.
Return to Telegram and unlock it with the fingerprint.
Try to interact with or close the mini app.
Repeat the test with the attach menu open in a regular chat.
Current result
After fingerprint unlocking, the mini app remains displayed but ignores all touches and cannot be closed. Pressing Back only sends Telegram to the background. The attach-menu case can additionally leave the interface zoomed to 1.25x.
The only reliable workaround is to swipe Telegram away from Recents.
Expected result
After fingerprint unlocking, the passcode dialog window should be dismissed completely so that the mini app or attach menu remains interactive and the interface returns to its normal scale.