Disney really swept this one under the rug, but apparently a cast member was injured when they fell in an area they were supposed to go. This refurb is chiefly to install safety gates in that area.Nope.
There was no mystery Cast Member injury but there was concern with guests, especially children, heading back towards the vehicles and the potential for injury. It's true that they're installing safety gates at the exit and the ride will be getting the same treatment in California when it goes down for refurb at the end of the month.