InhaleMyAnts

I discovered that this report is a duplicate of  MCPE-63416, please tag this issue as resolved, my apologies.

You're good to set this as a duplicate, 63905 covers the book inventory bug well enough.

Confirmed duplicate issues are tagged as resolved in the sense that the report made does not need any further action, but does not ignore the bug itself. Ionic linked the original case to the bug so any updates that someone has on the issue can go on the "main bug case," as it maintains a state of organization.

Has been observed in survival world with cheats on and a creative world with cheats on. A book & quill that is obtained via commands (/give @s writable_book) does not move from the inventory slot that is put into. For some reason, may have trouble replicating, but it is achieved through the steps above. This bug has a short-term fix of being able to drop the book and picking it up with the ability to move it. However, if the player places the book in a chest, closes it, and re-opens the chest, and puts the book back into the hotbar for writing, the book will once again be unable to move around.

Debug info: beta1.15.0.51 (cli-p392, s1770030287) SAMSUNG SM-J727P, Adreno (TM) 506, Android 8.1.0 FPS:48.1, Server Time:8.8, Mem: 278, Highest Mem:278, Free Mem:344, GUI Scale: 3.0

Seems similar to my problem, I'll drop my perspective of the issue in the comments there, thanks for catching that, searching for 'items do not move in inventory' did not yield me that.

@IonicEcko I've only seen this with a book, but I recall this happening another instance, I just can't remember which item exactly, and vaguely remember it being on a creative world. I tried replicating this bug in both survival and creative, but it did not occur, so I'll keep updates on this issue if they happen. I wouldn't say this bug is the same as Silent's  MCPE-63904, as this does occur in single player (not tested in multiplayer) with low latency, and there is no duplication or deleting of the book, it simply just reappears in the inventory slot it was first placed in. Worth mentioning though, should've been more specific on performance and game mode.

The very same issue with me, as well. Opened a backup world for my main world, and began to mess around on a copy. Frames dropped over 50% (from 60 to 30) in all dimensions, and seems to be only affecting worlds made before the Beta.

Edit: debug information for devs, beta1.15.0.51 (cli-p392, s1770030287) SAMSUNG SM-J727P, Adreno (TM) 506, Android 8.1.0 FPS:24.3, Server Time:8.8, Mem: 278, Highest Mem:278, Free Mem:344, GUI Scal: 3.0