Thank you for replying again. I'll send a few more points your way and we can drop it. I'll either accept it or go back to using something else.
Thanks to Ed for the suggestion. I was hopeful, but the sleep mode box was not ticked in the driver. The driver has been ripped out by the roots and re-installed. There is no noticeable RFI in the shack... the problem happens while receiving, so I should notice something in my signal and it's very good. Further, the problem goes away when the software is shutdown and restarted and doesn't rear it's head for some extended period of time. When the problem is happening, there are definitely extra characters being interpreted by the software.
Physically removing the USB connection while the software is still running, swapping cables, and restarting the polling does not stop the problem. Clicking the 'Test' on the rig interface page will always correct the current frequency, but will not usually follow a VFO change.
The very odd thing is It corrects itself when the ACLog, not W-10 or PC, is restarted and doesn't happen again for an extended period of time. And when it fails, it fails. I'm leaving it running and if it fails again tonight, I'll do some more testing for my benefit.
I'm fairly sure the issue is on the PC side of the USB cable. Software, Windows 10, Brand new driver (late last year) are suspect.
Ken - K4EES