Fla Animate CC 2019 does not work in Animate CC 2018

In Animate CC I added some movieclips with linkage name BlackMc with Javascript

for(var i = 0; i < 5; i++){

var mc = new lib.BlackMc();

mc.x = 200 + i* 20;

mc.gotoAndStop(i);

mc.y = 200;

this.addChild(mc);

}

I have put another movieclip on the stage by hand. Lets call it mc2

When I open this fla file in Animate 2018 and publish it there is a problem, the BlackMc Movieclips are in the upper left corner.

If there is no mc2 it works fine in Animate 2018.

If I export the frames and copy the Movieclip BlackMc in a new fla File in AnimateCC 2018 it will work.

I have also the problems that some files does not open in Animate CC 2019