I experienced a similar behavior last weekend during CQWW CW contest.
Both units connected on a local network, using N1MM+ and TS-480SAT.
Caught my attention the fact that I didn't receive any response to my calls.
The sound generated locally from the TS-480 unit was ok, as expected, but checking my signal on a remote internet SDR, this was unreadable.
Using the paddle connected to RRC, the transmission was ok, using the winkeyer through N1MM+ the resulting signal was unreadable.
Thought was something with N1mm+ setup and switch to DXLAB-Winwarbler, again, the same behavior, it works with the paddle and it generate the same unreadable signal through Winkeyer.
I didn't remember exactly the sequence of the operations but I've removed all RRC software and COMs and do a clean reinstall.
Finally it works as it should