Why did I lose my reputation on a migrated question?

Question

I asked a very good question that got many upvotes on Stack Overflow. I earned many reputation points on it. Someone then moved my question to Programmers. There was a duplicate of it on Programmers, so it got closed. The problem is, when my question was moved, so were the reputation points I earned on that question. Now, I have 99 reputation on a site I never use, and just a few on Stack Overflow which I use often. The reputation I earned did not say on Stack Overflow like it should have (Migrated posts lose their pre-migration reputation). Why?

Here's the question: Should I use a code repository if I am the only one working on a project?

Answer 1

You didn't read the Meta question you're referencing very carefully. From Nick's answer (emphasis mine):

You will also keep the rep on the source site, unless the question is deleted down the road (the same as any deleted content).

The Stack Overflow version of your question was deleted, thus no reputation (on Stack Overflow).

Answer 2

The question you asked was not a good, on topic question as far as Stack Overflow is concerned (in the opinion of those that migrated it at least), which is why you should not receive any rep for your Stack Overflow account.

It is a good, on topic question as far as Programmers is concerned, which is why you deserve the reputation for it there.

As far as the mechanism behind this is concerned, closed questions that cannot be improved through edits will eventually be deleted. This is what happened to the instance of your question on SO, which is why you no longer have the rep for it.