the survey bugs, items are not always loaded etc.
If you have too many images on a single page, then some limiters may become active, showing only 50 images with few seconds. Otherwise, there are no known bugs that would match what you describe?!
So, I'm linking these 4 questionnaires by redirect() which i put on the last page of the first three questionnaires.
I strongly recommend not doing so. You will increase complexity and that may result in errors. You may also have issues matching the different data sets if you mess up adding unique IDs to the redirects.
However, when this happens sosci provides this notification:
This is only when you are logged in, while testing the questionnaire. You can only be logged in to one questionnaire at a time. If you would like to test your construction, please open a "private browser window" in your browser and copy the link there. You are not logged in in that window (unless you log in there), and therefore will not be logged out.
This will greatly confuse participants.
Participants won't see that, because they are not logged in.