My mercenary is constantly trapping me in a cage in Ruthless

I picked a mercenary with Vaal Glacial Hammer, and he always traps me in an ice cage for 5 seconds in every single encounter. Sometimes he runs alongside me, we come across a single white mob, caged, wait for 5 seconds.

It's probably not as much of a problem in Standard but I believe this is an oversight in Ruthless, where we don't have blink abilities and we get severely handicapped by any terrain-modifying mercenary. I think I just have to dodge every single one of them, which reduces my pool of recruitable mercenaries for no valid reason