I have the same Dometic refrigerator as the OP does. When operating with propane, it does fairly well. When operating it on 120VAC, it takes more than 24 hours for the fridge compartment to cool, more like 36 hours.
In my opinion, the slider thermistor is a very cheap, poor design and is easily disturbed. Putting a dab of silicone on it to hold it in place should not be an option for temperature control.
I bought the "Dometic Repair Kit" from Snip The Tip and will be installing it next week. I have researched this item, thousands have been sold and placed in Dometic refrigerators with great results. If you look at the reviews and feedback on this kit, not a single negative comment from over 600 buyers.
Dometic should of design this better in my opinion.
2016 Forest River Heritage Glen 276RLIS
2012 Chevrolet Silverado LT 3500HD Duramax