Steve wrote:
On the 3.45-7.4 MC band (only), received signals are somewhat
distorted. Normally, when tuning in a CW signal with the BFO on,
you'd expect an undistorted tone as you tune. On my radio, it'll
sound more like a growl. Signal strength doesn't seem to matter.

For some reason some SPs have too much LO injection on one band.
Try lowering the 105 Reg with a pot and see if that does it...
73 W7ZFB