I have been playing a Mind Control/Electrical Affinity Controller, and I was teaming up with a friend playing his Storm Blast/Electric Armor Sentinel.
Reliably, every time, whenever my Galvanic Sentinel was within the AoE of his Category Five, my GS would immediately fly far out of the C5.
I can't tell if my pet is being Knocked by the C5 or if it just doesn't like sitting in it, but it is clearly a bug, as there is no reason my pet should have any interaction with his C5 at all.
I haven't tested this with a Storm Blast/Electrical Affinity Corruptor to see if it happens with ones own pets.