OH-58
Army, your notes refer to a Vne of 87 for that condition, but your posts do not say whether that Vne is a stall boundary or exists for one of the other typical speed limiting factors. I must add that for a counterclockwise rotor, a right rolling tendency attributed to stall is difficult to envision.
Here's a suggestion: get on the phone to Bell and get connected to their test pilot office, then talk to the guy who did the 58D structural demonstration for the Army model and explain your flight experience. He can get some assistance from his flight test engineering pals and most likely get to an explanation for this event. When you get it, post it here as it is most interesting.
Thanks,
John Dixson