One thing I noticed by the way, I thought I had three 10" screens, but I only noticed today that two of them are 8" and one is 10". And coincidentally the only screen that's faulty is the one 10" screen...
So I have two C4-T4IW8 that work perfectly fine, and one C4-T4IW10 that appears to have problems with the camera stream.
Could this then be a software issue that's related to the specific hardware installed? So for other 8" screens there wouldn't be a problem, only for the 10" screens?