I have the Liberty Air 2 Pro for a couple of days now. When I turn on any of the ANC modes, I hear a flickering noise from the Left earbud. There is not such a noise in the right one. I did the Fit test through the app and the seal seems good. Also I can verify that the isolation when I am not using ANC is good. This flickering happen only for the left earbud and only with the ANC on. This flickering noise is louder when I am in a call rather than when I am just hearing music.
Problem with anc mode
Have you try to probably reset the earbuds? IF still not work, I would send it back to soundcore for warranty repair.