Affects Version/s: Minecraft 15w34d
Fix Version/s: Minecraft 15w35b
OS X 10.10.4, Java 1.8.0_45 64bit, 1G RAM allocated
I was testing something in the End on the new snapshot. I went far away from the main island and started placing blocks - they didn't show up.
1. Go to the End
2. Place blocks in a line in any X/Z direction
3. Keep placing blocks until you reach a (empty) chunk border
4. Blocks after that border are placed invisibly
5. Re-logging shows those blocks
I created a new world, made an end portal, then started placing blocks as soon as I teleported. Then I did the same in 15w34c, blocks are fine. I also tested on a 2nd computer, also 10.10.4, also Java 1.8.0_45 64bit, but different processor and RAM allocation. Attached screenshot from that computer as well.