Indeed.

I’m not sure why you’re seeing these duplicated frames at all, especially in the 24p sourced material. There should not be any of this a and b or b and c duplication business. What software are you using, and what are your project settings (primarily, your frame rate?).

Using h264 and other compressed sources, I have sometimes had Adobe start to do what you describe, where it fails to render properly synchronized previews of compressed files that are actually synced correctly. It’s rare, but closing and reopening the software took care of it. I saw it more when dealing with that ET special edition thing I was doing, using someone’s TS file.

But between the duplicated frame talk, and that this seems wide spread for all 3 despecialized films makes me think something is wrong in your project file. There are surely some shots that aren’t perfect GOUT sync that slip through here and there. Harder to catch when they end up being balanced out by another nearby shot being one frame longer or shorter. But this sounds… worse.