looks like there is no fix to this, I'm getting the same issue on my computer.
When I try to mix videos it freezes but the audio keeps going. I have tried optimizing my laptop to serato standards, I don't think its a hardware issue, to me it has been a software issue.
I believe there has been no updates to serato video since i purchased it. Its still in version 1.1 something like that.

Serato Video works best with a good video card. If your laptops have a secondary video card then choose that card to run video. If not it's likely it's just the program I am on Mac with some of the best specs possible and I still have video freezes as well. They either should discontinue use of it or fix it cause we're getting ripped off for broken software and it's starting to piss me off😬🔥

Have you guys run the settings to use ffdshow codecs?

support.serato.com

lots of issues may also have to do with where your videos were sourced from...you can't just grab .mp4's from anywhere and expect them to work proper, get your video content from reputable sources, there are many encoders to render a video to .mp4 not all are good... finding sources that optimize their videos for playback in Serato would be another thing to look at

Ended up replacing my video card. solved the issue.

dang! does happen tho