I reported this phenomenon and provided every infos for checking. Here

Just now updated VEGAS19 to B458, the problem is still there.

1, the file is a ProRes video clip - its fps matches my project.

2, on the timeline, I give another clip with different fps to compare. The ProRes seems correct.

3, timeline zoomed, you can see a half red warning.

4, use the quantize script extension I get this result.

5, timeline zoomed, that phenomenon persists. This is critical if you wanna dect scenes and split a long/big source material - I mean material coded with ProRes, I don't know others at the moment.