Cannot crouch under water

When you tap the crouch button under water you still able to fall on the edge and use functional blocks and also the paper doll doesn't pop up 

Expected result:

After clicking sneak/crouch button:

• The paper doll will show that you are crouching

• You can't use functional blocks while holding items in your main hand.

• You don't get damage from magma blocks

Actual result:

After clicking sneak/crouch button:

• The paper doll doesn't show that you are crouching

• You can use functional blocks while holding items in your main hand

• You get damage from magma blocks