Why might an LCD/LED filter have an odor, even if the filter is in good condition?

The condition of your fume extraction filter displays only register a physical blockage, so it will not alert you to a saturated carbon filter unless the VOC sensor option is fitted to the machine. Any smell coming from the extraction unit’s exhaust is a strong indication that either the extraction is not adequate enough to contain the contaminant release, or the carbon in the filter has become saturated and requires replacement.

-John Podwojski, BOFA Americas