The Isolation Vault rising toxicity phase spawns marked enemies outside the cave now.

[NeoRetro10K]

This, in combination with the increased default rate of rising toxicity and the fact that it goes up even ridiculously faster if you go too far outside for some reason - such as, say, to kill the improperly spawned enemy that in so killing would allow you to reduce toxicity in the first place - makes this phase very inconsistent, and it is really far too punishing even without considering this bug.