I didn't need to invoke the act and never did.

never

I don't know how much clearer people need this to be, or how much clearer it could actually be.

It's not like the president to ever lie, especially about something important, and especially in writing. If he had ever invoked the Insurrection Act, IMHO he would more likely refrain from referring to it (or create an ambiguous statement that could be interpreted multiple ways) than lie about it and flatly say he never invoked it.