Whenever you press the D/Move right button in creative, you instead break a block when the button is held and place one when it is tapped.

Video for reference: https://youtu.be/8p8mJ1-YqdE

I do not know how to describe this in steps well but I will try.

1: Use the default touch controls

2: Trying moving right with the right button (not moving the screen)

3: Hold press it (blocks break)

4: Tap it once (blocks placed)

Observed:

Blocks break/place.

Expected:

Moving right.