Normally in minecraft, when you put a command inside a command block and control + middle click it; you receive the (+NBT) version of the command block. And this happens in forge as well. However, normally in mincraft, when you place it back down, the command previously in it is still there. This is not the case in forge, as it does say (+NBT), but when you place it down, there is not a command inside. This is extremely important to the mod I am currently making.
FULL LOG:
http://paste.ubuntu.com/11572530/
Mods: no mods at all
Version used (latest): 11.14.2.1433
no information relating to minecraft forge AND nbt tag command block bugs