i can't say what the problem is exactly
but in terms of troubleshooting, i always go by being able to fail fast so you can more quickly identify what the problems are and correct them
and this is if you haven't already done so... as i'm unsure if these photos are more for demonstrative purposes
as in, i don't know if you're constantly running tests on the whole body; because that looks like a heavier sim than it needs to be for testing/troubleshooting, IMO
cut a small subsection containing both where it works and where it doesn't
and then trial&error until it's solid enough to your standards (maybe then it won't require computer restarts)
then once you correct the problem, try applying the fixes elsewhere and see if it helps
and this is for the meantime, while or if someone who actually does know the issue firsthand and knows how to correct it--can tell you
but might as well learn during, right?
and might take some time... but hey
just an idea, take it or leave it, it's all good. hope it helps