This sentence confuses me...help!

No

No, Smile, I don't think so; but I'm not quite sure what you mean here...

Yes, it's OK but a little confusing.

since he has lived OR since he once lived
would make more sense in defining the time he became interested

I mean, "Jack has lived in Moscow."
Sorry about the typo.

What confuses me is that, if Jack still lives in Moscow, why can't I say "Jack has been interested in Russian history since he moved to Moscow." Wouldn't this make more sense?

Yes that's the implication

Nah 007, I should've realized

But the sentence means that he doesn't

You could indeed say that if he still lives in Moscow. You could also say that if he got interested in Russian history when he moved there, even if he had moved elsewhere and retained his interest.

The word 'since' could also mean 'because'. That is, Jack became interested in Russian history because he moved to Moscow.

I agree with your title. It is a confusing sentence.

Thank you guys for your help!