Same issue here, yet to beat it. Cannot target ads, valkorion heals himself once I have him down to about 25%, uninterruptible, satelle does not heal. I can hurt the ads with undirected aoe's, but as a carnage marauder, that does not do much.
I've tried relogging, stucking and trying again, going to a stronghold and then pressing play, and as a last resort, reseting the entire mission. all to no avail.
edit: ok, so the reset DID actually change something... the temp ability interrupts, which it definitely did not do before. Perhaps that may be the root of the bug,