Black screen on top of android app

REPRODUCIBILITY: 80%
OS VERSION: 4.5.0.19
HARDWARE: Xperia X III
UI LANGUAGE: en_uk
REGRESSION: This kind of bug is not new, just hard to catch

DESCRIPTION:

Instead of smoothingly passing from one app to another for authentification, there seems to be a conflict in which app is displayed that block both apps frontend. This bug happen often in this type of case (one android app taking the focus because of an action on another app)

PRECONDITIONS:

A Nextcloud account is needed

STEPS TO REPRODUCE:

  1. From F.droid, install Nextcloud Notes and Nextcloud.
  2. Log in in the Nextcloud app and leave it open.
  3. Open the Notes app, choose your account to login and click ok.

EXPECTED RESULT:

Focus is switched to the nextcloud app where you can allow access to your account

ACTUAL RESULT:

Focus seems to change app, but the app switcher is displayed on screen, meanwhile you’re still in the Nextcloud app. Both apps don’t respond, and trying to interact with the app often creates a black screen. Changing apps works, and the rest of the system keep functionning.

MODIFICATIONS:

chum is installed, but I don’t think there’s anything changing how app focus or android works

ADDITIONAL INFORMATION:

Here’s a bin of devel-su journalctl -fa while provoking the bug. Please let me know if it contains sensitive data