Hello,
Thank you very much for your question!
I agree with Barry, that there might be an active Graphic Override combination when you switch back and forth between different views and layouts. But, if you're sure the no Graphic Override combination is applied, please let me know and I would love to have a look into your project file.
Looking forward to hearing from you!
Best regards,
Minh
Minh Nguyen
Technical Support Engineer
GRAPHISOFT