My stat definitions are fine. As i said before, i asked now two of my friends to check this out on their PT4 and both have the same issue.
FYI, the VP$IP stat is not exactly the same as the VPIP stat.
There's no VP$IP stat in PT4. There's only VPIP and VPIP - Legacy which you're talking about.
For me it looks like default PT4 tries to put "VP$IP" stat into the HUD, but there's no such a stat so it's converted to text object. Just like while importing HUD profiles from PT3, it changes not existing stats to text objects.