I am experiencing the same issue. I have a dual skeleton/zombie spawner xp farm. All drops go into hoppers which go to a dropper, that drops items into a water elevator, which then flows over 3 hopper sorter cells. One hopper cell is for bones, one for arrows, one for rotten flesh, and then anything else will drop into lava. Just bones and arrows do fine, but rotten flesh falls onto the arrow hopper and just bounces there, but won't continue to the last water stream above the rotten flesh hopper. Any bows also get caught on the same hopper. It is the second to last, it is the sixth block from the source block.
Catlin Homer
I am experiencing the same issue. I have a dual skeleton/zombie spawner xp farm. All drops go into hoppers which go to a dropper, that drops items into a water elevator, which then flows over 3 hopper sorter cells. One hopper cell is for bones, one for arrows, one for rotten flesh, and then anything else will drop into lava. Just bones and arrows do fine, but rotten flesh falls onto the arrow hopper and just bounces there, but won't continue to the last water stream above the rotten flesh hopper. Any bows also get caught on the same hopper. It is the second to last, it is the sixth block from the source block.