Mag mines on TotP - per the other active thread now, as I’ve noticed it mentioned well before that. A known bug that won’t be fixed.
Cradle of Death with Darkness - not that annoying but need to be familiar enough with the map to know which Gatekeeper Constructs to look out for which guard the current active area. Got a random ally in last week’s mutator queue (In the Name of Love) who used the Brutal+ bug to play that week’s mutation. First thing I asked was “why? this is harder than the current weekly”. We got Darkness, went to the wrong bases, lost that one. Re-rolled again on random, got the regular mutes, completed it one go, despite not playing very well.
Darkness on any map that requires you to memorise enemy attack wave patterns to deal with effectively - eg TotP, MO.
Void Rifts, any map (except maybe VP) - pretty sure the rifts spawning at 2:20 instead of 3:20 was a bug/typo, but they saw how many pros worked with/around it, so left it as is.
Void Reanimators, Void Rifts, Just Die - FFS! I assume rolling all 3 is not possible even at Brutal +6 since it has a combined score of 22, and threshold for +6 is 19. Lucky us :-/
Barrier + Walking Infested and/or Alien Incubation + Just Die - All enemy comps would already be buffed. Now the extra spawns of broodlings and infested get that much harder to kill. An apparent workaround for Barrier is to one-shot the enemy units - but how many units do we have that do enough of that damage in a single shot and can be massed? Immortals, Siege Tanks, Tempests, BC’s?
Barrier on Dead of Night would be an absolute pain for the fist night. Most static defense doesn’t one-shot the infested. The first Shuttle on Miner Evac would also get that much harder to deal with.
The primary issue is that the mutator algo, how ever over-smart it’s trying to be but isn’t, just doesn’t account for or re-score mutators based on their interactions. As if that’s hard to figure out and add in to the algo.