I'm not sure if the center pin on the MVP is too loose, or the well is too deep. The VV3's have this problem as well. If I am not mistaken the 510 connection standard was only a diameter standard and not a "depth" standard. I know on my Evod, the Ego Collar would bottom out before the pin made contact.
A lot of us have asked innokin to resolve this. Either shave the 510 head down a bit, or better, make an adjustable center pin....Hopefully this will be resolved down the road.