Right after updating to version 1.2 for Mobile Version of Bedrock edition the crouch feature in the game usually will allow you to always put your shield up. Now it only works 1% of the time. Usually when you start from a load point and use crouch it'll work right away. It stops working as soon as you use any weapon while crouching with the shield. The shield will go to normal position and not be shielding while you're still crouching rendering the shield useless.

If I get out of the app, swipe it away, and get back into the game it'll work only until you attack with a weapon while shielding, then it instantly stops working/shielding while crouching. 

I noticed also if you crouch with the shield and it's actively shielding, it'll always work as long as you don't attack with any weapon while shielding in crouch position. Of course the only way to shield is to crouch.