The relatively new Card Configuration Preview feature triggers the fetch from the card to the microservice before the card is configured. The error returned before the URL is even defined gets cached, which causes some or all of the cards to throw JavaScript errors.
The relatively new Card Configuration Preview feature triggers the fetch from the card to the microservice before the card is configured. The error returned before the URL is even defined gets cached, which causes some or all of the cards to throw JavaScript errors.
The fix: don't cache errors :)