A controller performs background reads of multiple physical pages of a selected physical block of a non-volatile memory. The controller detects asymmetric transient errors in a physical page among the multiple physical pages based on a bit error rate (BER) observed in the background read of the physical page. In response to detecting the asymmetric transient errors, the controller mitigates the detected asymmetric transient errors by relocating valid logical pages of data from the physical page to another physical block of the non-volatile memory and by retaining valid logical pages of data programmed into other physical pages of the selected physical block.