Some GW cards is poorly produced. You may be just unlucky that got such ones.
There are guys reporting similar faults on Chinese Forums.
For the sake i would not post their names here, just to make a conclusion.
1.Some tf cards that not legit enough would cause errors, including freezes/ exit failure.
They even recommend me to get a C10 Sandisk or other brands.. (Note: Not kingston)
2.Some GW cards have already been confirmed to be bad ones.
Someone even just played for 3 hours, and got his card inavailable the next day.
He contacted the reseller and after confirmed that is really broken, the reseller changed his card.
3.Some 3DS Models including the first JAP models may even have faults in the 3ds itself.
Since you told us some clues, i think that is your GW red card got dead not your tf card.
Just ask for change the card. There are differences in product between the first batch of GW and the second.
Hope you enjoy yourself. If not believed in me you can try more methods. BTW cleaning is often good.