2018 Enclave AC musty odor

[kellae]

I got this car from my dad. It has less than 9000 miles on it. Love it but hate it. It's had a bunch of minor issues and the latest is the AC has suddenly become musty. I changed the cabin AC filter and the odor is persisting. Short of taking it to the dealer yet again, what can I do to eliminate this odor?

 

[MelsRegal]

Spray lysol or similar product into the duct work on both sides of the filter.
Do you have the system set to bring in outside air or Recirculation?