The top texture of TNT has become not to randomly rotate. The file "assets\minecraft\blockstates\tnt.json" was changed in 15w49b, but the "change" wasn't included in the official change log. No one even mentioned this until now. Therefore, I think it can be called "a bug" instead of "a change".
MC-99878
TNT top texture does not randomly rotate
Resolved
Duplicate
0
(Unassigned)
Unconfirmed
block, texture
Minecraft 1.9, Minecraft 1.9.1 Pre-Release 1, Minecraft 1.9.1 Pre-Release 2, Minecraft 1.9.1 Pre-Release 3
Retrieved
Intended as of MC-12959, the random rotation has been removed to fixthat issue