I can find old threads of this happening (2015) but didn't find any newer reports, though I may not have searched the correct string so if this exists in a report all ready, I'm sorry.
If my chest is full and I shift+click something into it, my items just disappear forever. I lost my diamonds this way when I was putting the stack back and opened the wrong chest which happened to be full.
I tried with some sticks and things like that, and sure enough, you can repeat this bug.
Linked issues
Comments 2
I was not able to reproduce this issue on Windows 10. I thought I saw a stack of items disappear once in the opposite direction (from chest to full inventory), but then I couldn't reproduce that either. Yet you say it happens consistently for you.
There is an existing issue, MCPE-23531, where this happens for a chest being carried by a donkey or mule. Would this apply to you? If so, please go to that ticket and upvote it, and also start watching it if you would like updates when something happens to it.
I was not able to reproduce this issue on Windows 10. I thought I saw a stack of items disappear once in the opposite direction (from chest to full inventory), but then I couldn't reproduce that either. Yet you say it happens consistently for you.
There is an existing issue, MCPE-23531, where this happens for a chest being carried by a donkey or mule. Would this apply to you? If so, please go to that ticket and upvote it, and also start watching it if you would like updates when something happens to it.