When the measurement mic is too far off-axis from a speaker - in this case, the center channel - MultEQ/MultEQ XT tries to boost the highs to compensate for the attenuated off-axis HF response. This could be the cause of the sharpness that you are hearing. The fix for this is to aim the center channel up directly at the ears of someone sitting in the main listening position. And that is where measurement position #1 should be when you redo Audyssey setup.
It might look odd to pull the CC forward and prop it up, but it is free.