vivo X300 Ultra reverts to stock launcher after exiting Album app

On a vivo X300 Ultra (Global), Niagara Launcher occasionally loses focus and the system switches back to the stock launcher after exiting the Album app, even though Niagara remains configured as the default launcher.

The user followed vivo's recommended configuration for third-party launchers. The issue persists with Niagara but could not be reproduced with Nova Launcher or Octopi Launcher.

Steps to reproduce:

1. Set Niagara Launcher as the default launcher.

2. Open the system Album (Photos) app.

3. Exit the Album app.

4. Occasionally, the device returns to the stock launcher instead of Niagara.

Expected behavior:
The device should always return to Niagara Launcher, as it is configured as the default launcher.

Actual behavior:
The device intermittently returns to the stock launcher after leaving the Album app.