Bug Report: Hero Magic Coat says it prevents interruption of Cast(Phen card effect), but it does not.
It's working fine as of 10pm PST, 8/6. Bear in mind that this effect is only for odd upgrade levels. I tested with a +1 and a +2. +1 did give the +20% Cast Time, and Uninterruptable Cast, while +2 gave +1 MDEF. So everything working as intended.