It's not the jump itself that breaks, it's storyAdvance that happens immediately after (and also entire scrollback history after that point). This is how it looks for me in 2.45:
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Hopefully this is more helpful.
Now about asynchronous bug - it's not about dissolveFader being called again, it's Update being called while dissolveFader is running. It's true that it's protected from being called again, but it's not protected from jump to different chapter happening from scrolling in Update method while it's running (at least it's not in the 2.45 code), so scrollback can reload script while dissolveFader haven't finished yet and then same issue as described above happens. Which is why I added (&& !this.isFading) condition for scrolling to prevent that.
We can talk on discord if you prefer, I think I joined it some time ago for updates but never used it.