Faraday Pouch for car keys

[GJonesy21]

I bought a pair of cases to protect our keys for the 2021 Qashqai, especially after reading about so many thefts from scum copying key info and nicking cars.

They worked fine at first, one for mine and one for the wife's, they protected the key and the car wouldn't open until the key was out of the case, all was fine.

However, a couple of months in and they seemed to have affected the keys, even out of the case and with a new battery inserted, the keys are very flaky, sometimes they work sometimes they don't. If the button is pressed on the fob they work fine but then sometimes the key isn't recognised by the ignition! Not too sure what the answer is... we have stopped using the pouches and still the keyless opening is inconsistent. (we've hidden the pouches!)

is there a way of re-pairing the key to the car?

I am trying the maker of the pouches to see if they have an answer.