This bug was happen when I play in survival mode.

Before I ride the donkey with attached chest and saddle I'm still can open up inventory and chest (block), but after I decide to ride the donkey I cannot open up my inventory, chest, or even interact with several items like crafting table, anvil, furnace, etc. afterward, even when I dismount  from the donkey.

I have also tested it on other rideable animal on survival mode (horse, mule, and llama) and the bug still there.

The bug seems occur only in survival mode since I tested it on creative and it's work fine. I don't know whether it happens on adventure mode.

Currently in Minecraft Bedrock Edition 1.15.0.53 Beta.