I made new attempt: I create a two new scene in sketchup with only text and the original scene without text. then I overlapped in layout the new scenes: the text one vector rendered and other raster rendered. The result is that some text are now invisible directly in Layout as you can see in the attachment...even stranger!
But the text in pdf export is very beautiful!
[image: MaFo_Desktopscreenshot.png]