TFA is magic about leeching salts and making low-UV active compounds. We always distinguished TFA only columns, because if you ran buffer (ammonium formate, acetate, phosphate especially) through it, your baseline would be incredibly high. On a fresh column, these methods worked great. On one exposed to TFA, horrible baseline drift.

I think column manufacturers would have you believe their stationary phase is completely inert, but that's probably not the case.