It's always been one of the issues with combining Minnie Van requests within the Lyft app.
At first, you couldn't get it to select MK as a pick up spot. The app knew MK was not a valid pick up spot. And it isn't for a private Lyft. You had to physically move the pin to MK for Minnie Vans
Now they've got it so it can drop the pin at MK but it isn't sophisticated enough to only give you that choice after you select Minnie Van.
It's where the human has to make the choice over the app. Though I'm sure some guests try to use regular Lyft and MK pick up and the drivers have to explain they can't do that