You really have an awful lot going on in that log and perhaps someone who has seen some of that before could make a bit more sense out of it but the thing i want to draw our focus to is the custom NVENC profile in FFMPEG. Does the problem persist using the regular NVenc plugin? Or with a more round number of lookahead frames and keyframes?
Like the last recording attempt shows a lookahead of 32 (30 would probably be better) and a keyframe interval of 59 (if you're using 59.998 fps. 60 interval would be better)
If you're seeing regular corruptions in your video then it does sound like keyframes are unreadable. It was even somewhat common when using the HEVC NVENC plugin... In fact. I just read the log again and saw that you're using it. It's broken.
Edit: Also yeah spotted the .Ts file usage. Do you need to use that format for any specific reason? Seems to have all of the same drawbacks as recording to an MP4 file. Can't you use the matroska (.mkv) container?
Yeah, I've a pretty complex set up (sorry for the late reply, I've been really busy this month).
I've been using that profile for a couple of months before the issue cropped up so it's a bit weird. I've recorded some tests with the same settings except I've changed .ts to .mkv, the HEVC to the custom H.264 one and the keyframe interval to 60 and looks like it's fine now, but I do need to bump up the bitrate considerably. I've had the keyframe interval at one second actually, but I guess changing the fps changed that to 59. That means that it's not the source either then.
As for .ts, it's a carryover from when I was using premiere pro to edit since .ts was the only multi-audio-track format that it accepted. It looks like Davinci does accept, so I might just use .mkv without remuxing then.