both seem to be of the sense to write [a memo] to

I'd agree with Jo that this isn't a common usage. You don't often even minute a meeting - you take minutes.

Perhaps it's primarily used in political/governmental circles. I think the implication is that you aren't just writing a letter, you're writing a pithy summary of salient points (minuting) and passing that on by internal post - like a memo but far more secure.

However, we used to talk about memoing people back before email became commonplace, so there's your noun verbing.

In fact when we first had company-specific (as opposed to Internet) email facilities we used to call emails memos.