Rarely arrows may bug out and stop working in the inventory. Trying to move them will result in them immediately going back where they were. Trying to add other arrows to the stack will cause them both to go to their initial spot. A similar phenomenon also occurs for some duped items however these arrows are not duped. Shooting a single arrow from the stack fixes this in its entirety.
Linked issues
duplicates
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Thank you for your report!
We're actually already tracking this issue at MCPE-70591, so I will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
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