Strange color artifacts when capturing Hi8 tapes?
 

I've been getting these weird artifacts that show up every now and then on some of the tapes I've recorded. I haven't found anything like this on artifact atlas, but you'll see it looks pretty bad on these yellow shirts.

Example

The artifacts do not show on my camcorder's flip out screen, so I'm pretty sure it might be an issue with my capture device, but wanted to see if this isn't a known analog artifact that I'm unaware of.

Any idea what could be causing this?

What capture card are you using? It looks like the yellow is somehow overloading it. If you're using VirtualDub, you'll want to check the histogram and adjust brightness and contrast before capture.

Sony camera > RCA to HDMI converter/upscaler > Flint 4KP Plus capture card > OBS recording mp4

It seems to pop up intermittently and is completely random from what I can tell.

Do not use OBS. That is streaming recording software, not for analog capture.
You're making your videos look bad by using it.

That RCA>HDMI converter method is junk, and will not work. What you see is what you get with it.