This bug has been on for a very long time ever since the Better Together update. It was a very hard thing to spot but when I made an item sorter in MCPE, I realised one item gets clogged up in the hopper that feeds items into the chest. So if I placed 64 blocks in the sorting chest, I only get 63. If I put another stack. I will get 2 stacks but 1 block missing which gave me 127 blocks not 128 blocks. It has been a reoccuring issue for every other item sorter. The hoppers item transfer speed is slower than in the PC version and item sorters of any kind will have this issue. I suggest that this issue be looked into and fixed. Mojang, you can take your time, because we find Quality over speed.

Thank you Mojang! 

• Paige043804