You are bound to see a L-N resistance with items plugged in, the resistance of the devices is probably less than a few ohms in total. You are measuring Millions of Ohms with an IR tester!
Unplug everything before carrying out IR testing.
The first time it was probably cold, so was effectively switched 'off' via the thermostat.
The second time it had been off for a while, so the fridge had warmed up and the thermostat operated. You were measuring across the motor, which would show up as a very low resistance.