No, you were bang on. PDO did cause muting.
Ok, at least it did for me! And I had (still have) the real deal (branded as Zemea), straight from the bastards that make it. It was almost impossible to get because of their restrictions on not wanting it to be used with vaping.
It solved the issue with PG sensitivities, but the side effect (flavor muting) rendered it null in potential use IMO.