Confirmed myself in 14w06b. I noticed that if I broke a block underneath a 1-block-thick ceiling, sometimes the drops wound up above the ceiling. Not 100% sure if ALL the "missing" drops wind up like this, but at least MOST of them do. (The dropped items are somehow appearing >=1 block above where they are supposed to be.) This still does not happen every time, only up to about 10% of drops do this. But this is very annoying, as blocks mined from i.e. cave ceilings tend to just disappear entirely.
Can't take pics myself ATM, but this happens to me too. MC-46890 has a pic, despite being a dupe of this bug. (Mods: Please mark it as such...)
Confirmed fixed in 14w05b. Most of the old item frames popped off upon initially loading the chunks in 05b, but after re-placing them, they all remained after reloading the world/chunks. Although, bizarrely, they now are emitting smoke particles, but that'll be a different bug...
Thirded for 14w05a, same behavior as before, same as above two comments. Not every chunk's item frames pop off, still same as before though.
Confirmed this myself in 14w04b, item frames in certain chunks are being loaded on the wrong side of the block, accompanied by errors in the console like this:
[15:53:37] [Server thread/ERROR]: Wrong location! (7, 29) should be (8, 29), sp['entity.ItemFrame.name'/996, l='Frontiers [snapshot copy]', x=127.06, y=69.50, z=472.50]
This happens every time I load the problem chunks, even after replacing the frames - they are always loaded incorrectly.
Confirmed in 15w51b, horses (and donkeys) will not climb up blocks while on a leash. Other passive mobs (sheep and pigs at least) have no problem walking up one block at a time, but horses will not. Thanks to this issue it is effectively impossible to lead a horse anywhere except short distances using a lead.