As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: MAIN CABIN FLOOR NEAR ROW 19 IS VERY SOFT AND FLEXES. MAKES POPPING NOISE. REMOVE AND REPLACE CABIN FLOOR BOARD STA 537.45-727B FLOOR (PANEL 144A5810-127) PER AMM 53-21-00. PANEL 144A5810-126 ON AALA202008159001.