Say a swashbuckler is high enough level to have subtle blade then they pick up a countering blade. Since the effect automatically fails does the swashbuckler automatically get the reverse attempt or does the swashbuckler no longer apply because their just immune to a dissarm attempt.
I don't see why you wouldn't. Countering only says that as long as the attempt fails it triggers, period. If you are immune to the effect than it means it fails if used against you, therefore Countering triggers.