The encoder phasing could be wrong IOW the ±10vdc command if analogue, is commanding wrong direction WRT the encoder.
swap the A and /A to the controller should take care of it or confirm it.
My first guess anyway.
Oops I see you tried disconnecting, so I would then opt for the resolver phasing? swap the sin/cos pair and try it?
Were these newly connected drives? Never ran before on this system?
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.