AtomicBlaze
Inspired
Sounds like a phase issue. Again: are you that all other parameters were set the same, for both sides?
I change the room parameters: room level, room size and mic spacing, and the high and low cut. Everything else is default.
I probably need to spend some more time with it, I generally always use the same 3 or 4 IRs so it might just be an issue with the combinations I am using.