Since the last big patch, the “Smooth Getaway Sidecar” mount has been bugged.
As I previously unlocked this during the original event, it still shows in my collection as “Owned”.
However, it is not available to use at the load out screen. Sometimes it appears as locked, and sometimes it does not appear on the list at all.
There is obviously also no purchase options for this item as I already own it.
So far have not noticed this issue with any other items.