Is this a MX problem or MP?
If I use Install & Play and I don't have MP open and I allow the track to open the program this happens on all platform tracks.

VIDEO

Ignore last few seconds but didn't realize fraps didn't record when I tried going to full screen.

Edit: I guess it's a ManiaPlanet problem. I just went into my track folder and double clicked a platform track and same happened.

I was going to say, report it here:
http://forum.maniaplanet.com/viewforum.php?f=427

But then I see you already did:
http://forum.maniaplanet.com/viewtopic.php?f=427&t=12891

This is odd, because I had this same problem with Canyon tracks when the beta first started. I reported it.
But I thought Nadeo fixed it in subsequent versions. I stopped having this issue.
But I guess it's not really fixed.