A-904 Shifting from 1st to REVERSE!

It's not the governor.lol
Are you absolutely sure it's going into reverse, or just locking up in two gears at once?
I have studied the hydraulic circuits and just can't see a possible connection for reverse to operate with the manual valve in the drive position.I don't think it's a hydraulic issue.
Has anybody experienced a sprag (roller clutch) failure?