The set-up: Mac G5 with Kona2 card playing 1080psf24 video to a 24" Sony Trinitron BVM-D24E1WU broadcast monitor (which is a CRT monitor).

The issue: Very noticeable flickering in highlights.

The suspect: the 24 fps frame rate (occurs with 1080psf23.98 and 1080i25 as well).

The mystery: it doesn't occur with 1080i30 or 1080i29.97 which reinforces the suspicion of frame rates, however the monitor does appear to be properly sync'd for each frame rate, which is what causes confusion for me.

If the genlock is correct, shouldn't that quell the flickering? Or is this going to happen no matter what due to the non-NTSC (29.97) frame rate?

This is normal behavior for that monitor and those framerates.

At those framerates, the raster is scanning at 48hz and 50hz, respectively. Couple that with fast phosphor decay times and you get flicker.

If you use a Kona3 card you can have the card add pulldown in hardware and drive the monitor with a 1080i29.97 output.