Trouble combining scenes in one course

Hey there,

I have created ten quizzes in ten projects. Individually, they work fine. I now want to combine them into one project. I have copied the scenes and added them into a new project. Here, I have created a master menue in a new scene, in which one quiz can be selected and to which users can return after finishing their quiz.

Unfortunately, the layout of the correct, incorrect and try again layers in each slide of each quiz is now failing (only the buttons are correctly visible). Does anybody have a similar experience and advice for me what to do?

I am grateful for your clues

Michael