Since we upgraded to 2023.2.x none of existing projects can keep sync on the GPU HDMI output which we standard use (Deckink card mainly used for inputs only). Every few seconds there's a huge frame drop, and the HDMI output frame-rate is constantly jumping above and below the selected frame rate, and therefore not smooth. Turning sync OFF on the HDMI output, makes the frame drops to be gone. I also tried the Tutorial examples like the Lower Third with the same result. The scrolling of the banner is really bad. Tried multiple exact i9 machines RTX3080 with same exact result.
When I choose the output via one of the Blackmagic Decklink outputs instead (8K Pro in my case) and set the Sync on that SDI output the output is rock solid at 25p. Also on the GPU HDMI the output becomes smooth as butter at that moment.
I tried 2023.2.0 and 2023.2.1 with the same result. Updating the Decklink card with latest 12.5.1 driver did not make a change either. Hopes this helps development debugging.
I use the GPU output as well and I have experienced the same issue with my Blackmagic Decklink QUAD HDMI capture card. I have been told by some people I should never use GPU output as a program out feed, but I don't have an extra slot in my Motherboard for a Blackmagic HDMI output card. In the meantime I am using the GPU output without SYNC for my program out.