Burnt Initial Frames and Speedup Problem with WAN 2.2 T2V A14B at 121 Frames

The issue is fixed if I change the frame number from 121 to 81. WAN said their model is 24 fps, so I set it to 121 frames. But when I generate it, the result looks sped up and the first few frames always come out burnt. If I use 81 frames at 16 fps, it looks normal and plays at the right speed. Is WAN 2.2 T2V still actually 16 fps