[Fern]

To be honest, I have never seen Black Bubble shut down a Priest with ease before. The only times I've seen it happen are when the Priest stays within position without packing any form of status resist or even silent prayer- and Priests are usually packing over 160%+ status resist. I think this doesn't really need any form of change at the moment, specially when there's many ways around it:

A) Positioning yourself in such a way that prevents the enemy from using Strangling Etacof in the same round.
B) Running far, far away.
C) Sanctuary, the most common choice.
D) Heron Feather, the -1 silence duration accessory.
E) Status resist, which Priests usually have due to almost always building FAI/SAN at once.
F) Sanctified Boots, which halve the effects of black water.
G) If you happen to be a Galren Evoker, you may as well blast off the water tiles with Magaisendo if you really need to. But you can usually just walk/blink away.