Replace Specific Frames and Interpolate Them?

[Selur]

Unfortunately, it does not appear to be doing anything.

Okay. You did use the Vapoursynth preview to check that before encoding, right? (at least to make sure your settings are correct)

I'm going from Huffyuv>deinterlace to UT Video (for editing in other programs)>Encode to UT Video again, but with Frame Replace Filter

According to the debug output, no deinterlacing is done, since the source is detected as progressive. This will disable the deinterlacing.
If your source is progressive and not properly flagged, then you should let Hybrid know that by setting 'Filtering->(De-)Uninterlace/Telecine->Overwite input scan type' to the correct value. Note that if a source is loaded and detected as interlaced, the 'Auto deinterlace handling' setting isn't there,....

I will also note that the mp4 is not my source.

As the source was too big to attach (even for 5-7 seconds).

Then upload a portion of your source somewhere i.e. GoogleDrive or similar and send me a link via PM, in case it's privacy relevant.


Cu Selur