“The Max charge you’ve already paid” should be refunded when you contact them to explain what happened so there’s no “benefit” to be had from it.
In that situation, I’d probably tap in and out of the original station with no service to make it clear what I did and then in again at the alternative. It would be nice if there was something more technological to handle these situations but I don’t know what that would look like.
Before the hopper fare, getting kicked off an early terminating bus gave the option of getting a transfer ticket but I don’t know if that’s still done since the hopper would absorb most consequential problems.