Elemental Hit of the Spectrum bug in Lab Izaru fight?

Not sure what mechanic is doing it, but for some reason I now experienced twice dying randomly to Izaru on the last stage.

No incoming damage animations and no MS issues, I've recorded both deaths and they seem to be related to some reflect damage that shouldn't be there(?)
I'm using the new Elemental Hit of the Spectrum, I'm guessing theres a mechanic in there, that makes this fight impossible unless you can survive your own hit?

My best guess is, that the damage comes from the AOE effect of the gem(?)

I just beat Izaro with Elemental Hit of the Spectrum no problem.