Issue all layers completely filled in manufacturing plots

Recently I updated from PCB Version 12 to 13. My board designed using version 12 was properly manufactured, but when I now open the same project with version 13 all manufacturing plots are completely filled. The issue best can be seen with the Top Silk screen, where only the text should be rendered, but not the empty space. The "Top Silk Screen.png" shows a copy of the manufacturing plot, while "ShouldLookLike.png" shows the layer in the Design view. Similarily all electrical layers just look like completely filled Cu planes. The issue can be verified in the pdf plots, but my Gerber plots show the same issue. 

Could somebody please help to repair this issue?

(I followed the update recommendations for switching to version 13)