Maybe. It could also be some bug, or misconfiguration, version conflict, or whatever in their interview problem repository that they haven't fixed, because no interview candidates want to admit that it took them 3 hours just to get it running. Their actual production code could be an updated version of the same code, or different code altogether. In other words, this could be a perfectly good company, but the engineers don't spend time debugging the interview process when they aren't asked to.

I would agree that companies that give "2-3 hour" take home problems are a red flag for me — red as in, I won't do it anymore. That situation becomes an arms race quickly: if I can solve it in 3 hours, why not spend another 3 hours doing a second, more elegant solution that makes me look even smarter? I'm sure that's what the other candidates I'm competing with are doing. And if they're spending 6 hours, I should spend 8 hours at least, to get an edge over them. But they know I'm spending 8 hours, so they're probably spending 10...