This report is a revisited ticket of MCPE-25778. My original Wording was admitting quite confusing, so I'll be very blunt this time:

Let's say you are holding the forward key down your player will move forward. Then you open your inventory (chest, etc.) and back out with those keys still held, the expected result is that you would continue moving forward again, instead you don't move until you repress the key.

This can also be seen when holding the mouse down to place, break or interact with blocks, when you swap hot bar slots (using the mouse wheel), the input stops and you will have to repress the mouse click again to start breaking,placing or interacting again.

This has been an issue for as long as I can remember, it's not new. Hopefully this issue is easier to understand than my last report.