Twitter Card cache refresh time?


I’ve noticed that when I share an old link that I’ve shared before, Twitter uses a cached “snapshot” of the iframe contents for the card. I get why Twitter does this, but recently I changed my mongo server, and now when I try to play the twitter card (it’s a sound clip) it shows the server error from the last snapshot.

How often does Twitter refresh these snapshots, if ever? When a link is shared, are the iframe contents forever frozen in time?