I was about to post this as a question, but fould the answer just before posting.
Just post it now as a tip in case anyone get into the same situation.
I have this program that I want to run as an unattended server, and also be able to access the program remotely using Remote Desktop or TeamViewer on a Windows pc.
The problem was that everything was working fine until the HDMI screen was turned off. Then all output from Hollywood apps stopped updating. All other content on the host window seemed to update fine. I discovered the same issue happened when playing a video in VLC. For VLC it could be resolved by setting the video output to Windows GDI output.
So the solution for my program was simply to enable the Hollywood software renderer by using the display option 'SoftwareRenderer = True'