The 210 seems to have lots of grounding issues, I'd run a temporary ground to the socket and see what happens.

Many cars have moved to a shallow lighter and socket while power ports have kept the deep socket, this would explain the fall out.

These power adapters use an inverter where DC is chopped up at high frequency *, sent to a transformer then rectified into DC. ( Home power adapters rectify AC into DC then do the same as above. ) This process is electrically noisy and can cause problems if the car side of the adapter isn't properly filtered.

* High frequency is used because tranformers can be very small making for good packaging.

High intensity LED lights use the same technology and can have the same problems. In order to attain maximum brightness, current must be limited making an inverter the best choice.