I had an MSV2 that would not fit properly in the M90 frame. Not sure if its the same/simliar issue, but apparently the point at which it actuated the "pin" was farther forward than normal. When I pushed back the lever to fit inside the M90, it would engage the pin and leak. Maybe yours is right on the cusp? Try a different MSV.
You can't really tell the video (the intellimount is in the way) is the lever resting on the frame when its pushed forward? You could try cocking the msv a little bit to be more parallel with the front strap on the frame if it is hitting. That's all I've got, mine leaked like that when tuning it initially. My lever is parallel with the front strap, like this //, yours is like this /l. Could just be the frame ergonomics though since mine is in a regular I frame?? Good luck