@Mark good idea, though unfortunately this introduces a heat source.........(
@Joey Hess I just enjoy trying to visualise system behaviour from historical data.
I've done a lot of industrial refrigeration, blasts, precoolers, stores, tunnels etc, but all of those are with our probes deliberately positioned in moving air (with the exception of multiple wall probes in large coolstores, where we are wanting to know if we have any 'warm' sides/end/corners.
As @emile said, probes in still air are fickle and very dependent on location: if your probe is close to or over something that is behaving as a relative heat source, then you get an elevated reading: in food processing rooms with temp compliance issues, we sometimes have to set up probes positioned away from heat sources to avoid this local effect.
In the case of your fridge, I am mostly interested to see how it behaves once the contents are pulled down to temp.
Thanks for the ongoing insight/entertainment!