Hi Ari, Jason,
Thanks for your feedback.
First, unfortunately it's as well by using built in apps (i.e. Amazon prime). So also not only while casting (also was testing with/without Bluetooth, ...). Second, yes I'm using the manual side projection mode. Because the MogoPro is directly next to me (left from my bed). Necessary because of a small flat and the necessary distance to the screen for a bigger picture.
Thanks for the advice, I will try the auto front projection mode for a while.
Hopefully this will fix it, even the fact it would be quite sad to lose the manual side projection function becauseof that.