Sekonic L-858D spot meter issue

I'm having an issue where the spot meter shows a completely different value compared to the incident meter. When I measure in even light with the dome up, I get a reading of f/11.0 with incident metering, but when I measure the same light off a gray card using the spot meter, I get f/16.5. The incident reading matches my other meters, but the spot meter does not. Everything started after I did a factory reset on the meter.