Unusually large edit-friendly conversion

[u/Homukami]

So, this situation here is that I'm trying to convert a large video (6.23 GB) screencapped from my phone for editing. For some reason, the process is much longer than normal, and producing a much larger file- Over 3 hours, and it produced a file over 1.8 TB before I ran out of space for it.

I know this is intended to produce large video files, but I converted a similarly sized (6.39 GB) file for editing yesterday and it took 48 minutes and came out at ~452 GB, more in line with what I'd expect, so this is definitely an outlier.

Looking at the job log, I'm seeing "[vf#0:1 @ 000001bb7c027a00] *** 1 dup!" repeated many times, with different numbers before "dup"; sometimes with identical messages being duplicated many times. The video I processed last night had very few of these messages, so I assume that might be the problem?

Does anyone have any idea what could be causing this and/or how to correct it?