Maybe there is a bug with Heating up proc (he doesn't have delay), not Scorch?
http://us.battle.net/wow/en/blog/7207170
So, Heating up should have ~0.5 sec delay on removing.
Declined.
On this video
i found a two proofs.
2:43 - 2:46 - Pally with freedom, then mage uses a frostjaw and pally get a silence (without the root).
4:07 - 4:10 - Pally in frostjaw, then he uses aura mastery and frostjaw root+silence was removed.
The same as our server.
Declined.
I tried to use infernal blast on a priest with shield and i get a heating up proc.
What about immunities (like ice block, divine shield and etc), it does not give you procs, but this is intended. Proof:
Look at 2:00 - 2:06.