In my opinion all politicians are at least a little shady, but even I heard these rumors several months ago, so I’m sure “insiders” knew about them way before last week. There really was no need for Trump to “leak” them, they were out there for a while. Also, it seems many sources are contributing the leak to Rubio.
Who says he leaks them? This sort of thing follows every campaign and gains plausibility because every major candidate is a celebrity, and celebrities are small gods and capable of raising and dashing our hopes. They are people we do not know but think we do.