A few days ago I had my OEM tires replaced. The gentleman running the shop replaced my metal valve covers with silver plastic covers. He said that the metal covers can get corroded to the valve stem and sometime requires a wrench to remove. If the cover is too tight or stuck you can run the risk of snapping the stem, lose all your air and require complete replacement of the TPMS "transmitter".
So, long story short, I suggest switching out the metal covers for plastic ones.