OK, now I kind of know what's happening.
So I have a Video Capture Device on Source Record, specifically an Elgato HD60+.
Sometimes, I Deactivate the source while recording to kind of 'refresh' it, since there's some stuttering at times. However, when I do this, it seems that is when Source Record kind of weirds out and doesn't exactly stop recording, but rather just gets confused and gets stuck. Even after I re-activate the device, unless I exit OBS, make it crash, and re-open it, the source record doesn't continue.
Might file this in the github later, although the repo seems kind of dead...