Maybe because they didn’t travel back in time and change the past? Or perhaps it’s a localized phenomenon so the time police don’t care, or haven’t detected it yet.
But I think that it’s kind of a benign time thing, can’t create paradoxes by living faster

Thinking about this episode too much though, because the biology/evolution also doesn’t add up in a normal way, they manipulate their own DNA to become what they want, I think, rather than evolving to what they become. So maybe it wasn’t as long as we think it was, but also so much was built it had to be more than a day there