Roooh! Shit!
That's it
@TerryRed ! You spot it!
Since yesterday i try to find why on 2 parrallel installation, "bug" is here for one, but not for the other... And then appear or disappear when I overwrited file from each to other...
I forgot about the bands shape calculation ( which depend of FP option for accuracy ) on FP, wich depend of their point in editor.... I presume it calculate the shape and store it in a file when you launch it for the first time. And it could be random.
I just test with an invisible Rubber, and it fixed it!
Why i didn't though that! raaaaaah!