Game Controller Mapping Issues

I’m struggling with mapping my controller.

I have built a map with the included app in the test folder of SDL.
It recognizes the controller, but the mapping doesn’t change.

I am loading the mapping via SDL_GameControllerAddMapping(const char* string)
This line is before I open the controller.

I can subsequently get the mapping back with a call to SDL_GameControllerMapping and it matches what I loaded.
However, if I press the button on my controller that I have mapped to be A, it comes back as Y. B comes back as X.
If I go into the controller mapping string and switch those buttons, I see zero change in behavior. A still is Y, B is still X, etc.

Alternatively, I have also tried to open the controller DB with a call to SDL_GameControllerAddMappingsFromFile(“custommappingsdb.txt”); and get an SDL Error that says Invalid RWops

The custommappingsdb.txt file is sitting in the same directory as my application.

Any suggestions ?