Is it a audio drifting issue (it starts at 0.5s but then gets more out of sync)? Does you tv have a 3.5mm headphone output you can run into the line in on your Motherboard to see if it still happens? I have had some issues like then then pulling certain audio formats going from the PS4 - Monitor - PC since my capture card does not take audio.

It may not be the capture card but the tv that is creating the audio desync.

You should be able to add a delay to your video input through OBS as a filter.