Clips with lower FPS from posterize time aren't matching with the exports FPS

Hi there,

I'm trying to export some clips at a certain FPS so that they become a bit easier to animate in Adobe Animate, however I'm finding a seemingly large issue.

I have my clips all set to 6 FPS with the posterize time effect, in the export menu I have it down as Quicktime in H.264 codec, with the only thing changed being the video FPS which I have set to 6 FPS to match with the posterize time.

Is it possible that the export could be grabbing the wrong frames? I am quite confused with the situation to be honest. I've tried on higher frame rates within the export and it's still come out weird. I'd prefer to keep the posterize time the same just so it's a bit easier later, but at this point I'd be willing to try anything.

Thanks in advance for the help!