Film isn't like milk .
Film changes over time.
The extent of that change is affected by temperature. Refrigeration slows that change considerably. Storage in a freezer slows it even more.
Most likely, your film spent more time at room temperature before you put it into the refrigerator then during the recent "power off" event.
If you had two batches of film from the same emulsion lot, and one had stayed refrigerated throughout while the other was allowed to warm, you might be able to detect a tiny difference - if you were Photo Engineer .