I think I figured it out.

I lowered the BAUD rate down until I got to 2400 and things seem ok at first glance. Since the PC didn't want to wait or wasn't receiving the CTS flag fast enough, I guessed that lowering the transfer speed would give it more time to react.

I have to go line by line to make sure no garbage crept through isolated areas, but the records line up and look good.

Robert