Summary:
After fix MCPE-137647, if you start toggle the light levels with the right button and move, you can switch the light levels by aiming at any blocks. If you stop the movement, the light level switching will end and you will place a light block.
I encountered this bug while testing MCPE-135669.

Steps to reproduce:

1. Place the light block.
2. Start toggling the light levels at the light block (holding the right button).
3. Start moving (without releasing the right button or stopping).

Observed results:
When you are no longer aiming at the light block, you can still switch light levels.

Expected results:
Switching the light on the light block will only work when aiming at the light block.

Video:
Minecraft 2021-12-01 23-44-56.mp4