Sorry still don't understand exactly what your setup looks like and how you've performed measurements in REW.No.
L&R and subs. It Are the same postion and 1 minute after.
Yes, I can try later to do that.
Do you have 2 subs and you've selected "Bass Control > Off" in the purple case? If yes DL optimizes each sub individually and the combined result can lead to distortions like what you see in the purple curve. It has been discussed in this thread multiple times that this procedure is flawed and will ultimately result in an unpredictable and undesirable response. It's bad practice. Not sure why Dirac supports this in the first place.
Could also be a problem with your JBL/Arcam AVR. These units have had a plethora of firmware bugs. You would need to do more investigative measurements to get to the bottom of the issue.