DIAGNOSIS The machine did not register the filter reset procedure after the last filter change. The internal timer is still counting down from the old filter.
FIX Perform a manual filter reset. With the machine on, press and hold the "Filter Reset" button on the remote for 5 seconds until the light on the base unit goes solid and then turns off.
IF THAT DIDN'T WORK The filter may not be seated correctly. Power off and unplug the machine. Remove the filter cover and reseat the HEPA/carbon filter combo. Ensure it clicks into place fully. Reassemble and try the reset again.
HEADS UP The filter life is based on runtime, not air quality. If you run the fan 24/7, the light will come on sooner than the 12-month estimate. Ignoring it will not hurt performance immediately, but airflow will drop over time.