When exiting the setting too fast the Bluetooth connected mouse fails to fade and sync with player movements but it can still be used to break blocks. By moving the joystick it is then resynced with Minecraft. The main cause seems to be moving the mouse on the pause screen then simultaneously clicking the resume game button with your finger.

Steps to reproduce:

1. Tap the pause button
2. Move the mouse on the pause screen
3. Simultaneously  click the resume game with your finger