Ok, a small update here.
Fabi was so kind to send the obj file and procedure, and the issue is reproducable. See screengrab.
But only the preview is afected, the render is always good.

To reproduce?
Run a default clothsimm.
Then add some morph targets (I added Width1 and Bottom wide)
Then spawn an new Morph target => See my funny name. LOL.

Zero dyanamics, zero the morphs, set your new dial to 1 and testrender.
So far everything is looking GOOD, absolutely NO issues what so ever.

But, then turn your newly spawned dial up or down and you get a preview problem => See screengrab.
Only the preview is afected, the render is always OK.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!