Summary:

The crouch button does not visually correspond to the touch when crawling or sneaking, which can cause player confusion due to not knowing the character's state.

Steps to Reproduce:

1. Launch Minecraft mobile
2. Make a tube one block high and one block wide, or crouch below 1.5 blocks high.
3. Enter the tube, using a trapdoor or alternative method.
4. Make a hole in the block in front, then press the crouch button and try to fall into the hole.

Observed Results:

When you are already crouching or crawling, when you open the crouch button, the button will not respond visually, but functionally. This measure is used to know whether or not the player will fall from a block when he goes to its edge, however, this does not work in this case, changing the player's state, without him knowing whether he will fall or not.

Apparently this also works when the "hold to crouch" option is also disabled.

Expected Results:

The crouch button should visually match when the player is in a crawl or sneaking state, changing according to the player's click

Notes: 

The bug occurs on all touch controls.

I advice to look at the moments that i press to crouch in the videos. The button will not change visually, but my avatar will do actions, according to it´s state

In the video, I have the "hold to crouch" option disabled.

Images/Video attached: 

Yes

Notes: 
Due to the button visual bug, my interaction with blocks is also affected. I can't interact with blocks like trapdoor, by crouching.