I am guessing but check your fridge's climate control setting.
If the fridge heater is turning on, the power draw will increase RPMs on your generator when it is in ECON mode.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW