This isn't really a bug report, my render was glitched. But I wanted to show it anyways because it's so weird :0
I get the same thing in survival, just with trees. Pressing F3 and A together seems to fix it. From looking at it, when you switch J&H servers, it'll remember a chunk from the other server, displaying it only at certain angles. F3+A forces your client to reload nearby chunks, fixing the problem. However, this is only an assumption, and could be horribly wrong. :p
