Thank you for your suggestion.
I tried swapping speakers from side to side and the system is still skewed to the right. Will try swapping speaker cables today.
Have you measured the difference? I had REW measure for each speakers and the in-room Frequency response do look different.
Does a balance control fix it consistently? I tried balance control on my receiver but when the vocal is dead center, bass or treble would be skewed to the left.
I have never tried placing both speakers exactly parallel, will try it today too.
Just to make sure that you are not doing anything unnecessarily.
Swapping speaker cables means only swapping right and left on the speakers (don't swap them on the amplifier!). If the problem persists and doesn't move, it's not your devices or speaker cables.
When swapping speakers, you should mark the exact location on the floor to get the same positions.
Physically swapping the speakers (right cable stays right, ditto left) rules out a problem with the speakers.
Only if the problem doesn't move both times can you rule out a hardware problem and only then does a more detailed analysis make sense, otherwise everyone is just chasing unicorns here.
Then you should measure and mark the exact location of the speakers (adhesive tape, pencil, etc.), in the middle of the wall, right/left and listening position. First listen parallel and then again at an angle.
Please measure precisely with a ruler. I would place the speakers a little wider, the same distance from speaker to listening position and speaker to speaker.
Again, in the picture the left speaker is more angled and is further away from the wall. The measuring point for speakers is always the front baffle.
And finally, you would do yourself a favor by laying a carpet in the room that reaches at least from the speakers to the listening position and is wide to the outer edge of the speakers, or larger.