When setting the frame rate to 20, the image is (much) brighter than at frame rate 15.
This indicates that the frame rate is in fact slower.
I actually fixed this a month or so ago but forgot to update the new firmware to our GitHub Repository. I'll upload it this week.
Hello again Nikolas,
I have updated the firmware which can be found here. Please update your system with this new firmware and, if you don't mind, report back on this post confirming that it fixed the 20FPS issue. Thanks!