Does the same thing as exporting 
Still an issue 3 weeks later. Temporary solution is to go through every scene in sketchup and tick all the boxes for each scene in the model. Pain in the ■■■■ but its the only way to get it to display in layout/pdf properly.
The other thing that has now started to commonly occur in LayOut though is after saving a sketchup model then going to layout to update the reference, Layout just stops responding and will crash. This seems to be random so far, but generally it will crash once doing the update then wont crash again (unless another updated may cause it[varies])
Feeling your pain @Pjs , I am astounded this is still not fixed. This problem has existed since January!