I was trying to make a Pigman farm in My own world, and for some reason I never got any drops. It wasnt a problem with the spawning and death (I watched as they fell down onto hoppers) nor was it an issue with Hoppers. I went and found that-for some reason- My dispenser Vertical transport system was Spitting out items.

Going to my Superflat world, I re-created the same machine and tested it. It STILL spat the items out.
(attached files are the simple transport system and what happened after an item was put into the dispenser)

As for the boats-
I was building over a large quarry in my survival world, using the boat technique to get across it quickly, when I re-loaded the world, I got into the boat to go to my Mob grinders, and they fell through the 1-block deep bridge they were sitting on. I used shift and got out, and then was teleported back on top of my bridge, with the boat gone (and if I stepped into where it was, I got the shaking "Block error" effect)
I'm playing vanilla Minecraft. Help!

Note* I tried changing the Dispensers to Droppers and had the same issue