Intermittent defrost timer?

My refrigerator section was too warm but the freezer was working fine. There was snow/frost in the back of the freezer and no airflow to the fridge section. I left this unplugged for a few days and now I tried it and there is good air flow to the refrigerator so I am suspecting the defrost has an issue. I put an OHM meter on the heater and it has continuity. I moved the timer manually until the compressor turned off and one time it turned back on in about 25 minutes and another time it seemed like it didn’t so I started turning it again and it immediately turned the compressor on…maybe I was impatient…or is it possible for the timer switch to be intermittent? I’m also going to check the defrost thermostat but I have to stick that in the freezer in the garage to test that. Is it possible for the timer to be flakey or do they simply work or not work? Thanks for any input!

Yes it is possible to have a “flaky” defrost timer, but it is not a common problem.

It is, also possible to have a “sticky” defrost thermostat.

You may want to replace both components.