Immutable and Adrenaline on Stun Mastery

Adrenaline on stun mastery (Gain Adrenaline when stunned, for 2 seconds per 100ms stun duration) does not proc if running immutable unique gem. Is this intended?

I know this is a super late reply, but I was just looking into this mechanic as well, trying to see if it would work to proc First to Strike, Last to Fall on a champion with the Immutable Force and Bloodnotch combo.

If it doesn't work, I am assuming it is due to the Stun Mastery's rules stating gain adrenaline when stunned, for 2 seconds per 100ms of stun duration. I am imagining that Immutable Force may be lowering your stun duration to less than 100ms, which may not even proc the initial threshold for that mastery.

I am hoping that I explained that in a way that makes sense. Alternatively, it could just be a bug as well!

Bumping this up, the bug I saw here was the lack of a visual indicator sometimes when adrenaline procs when pared with immutable force, as well it not removing ailments. It now removes ailments correctly (as was noted in the patch notes) but does not seem to function at all in ancestor league, while working perfectly fine in standard. All you need to replicate this is an immutable force of less than 850% stun recovery, allocate stun threshold as a % of es and have no es, stun mastery for adrenaline, and First to Strike, Last to Fall allocated from champion.