I suppose if you right clicked on a module in the dl box and selected a zip (rather than a dll) of the wrong version, it might take the dll and give it the wrong name. Then you'd get the wrong version without an entry in the ini file. Or a theme could wire this wrong by listing an incorrect zip file on a *NLM line. Or a server could send the wrong zip file. (and of course there's no way for NLM to know what version the dll actually is)

If it happens again, you might try doing a !NetUninstallModule for the version that it's trying to load and then recycling. That *should* delete any wrong files/mappings.