I just watched it too. There's definitely something very wrong with the recording or exporting process because not only does it have those issues, I was watching it in 1080P and that is definitely not the correct resolution, even for YouTube it looks like a very, very low bit rate, understandable if using Twitch to do the actual recording. I can definitely see the issue in your newest video too.
The thing we'll need to know is; where do you see these lines? Is it only after you export the video, or do you see this in the recorded raw footage as well?
You'll need to narrow it down and figure out what to do from there. If it's visible only in the exported video, you need to check your export settings.
If it's visible in the recording then you need to check your recording settings although I'd advise against using Twitch to record things because the bitrates will be so low it ruins the quality by the time you upload it to youtube. I honestly think your issue is using Twitch to record it. If you have a Windows 10 PC you could try looking into using it to capture your Xbox's DVR. I'm not sure if you can but it seems like there's an option if you push the Windows Key + G.