Depends on how the software is set up to handle the m2v data; whether it is set to telecine or not.
I figured out the problem, turns out VirtualDub-MEPG2 has a setting enabled by default called honor “repeat first field” flags which apparently I had completely forgotten about (it’s been years since I actually worked with DVD stuff so I’m a bit rusty with the settings from a fresh install of VirtualDub-MPEG2), turning that setting off restored the original progressive image and framerate to my DB DBOX Vol 1 single and thank god, I just thought my memory was off and I was going crazy, good thing I wasn’t.