Lingvist graduate

is there any kind of cache that lingvist app has, as although it does prevent you doing anything when you don’t have connection, sometimes connection is poor and what you do doesn’t seem to save. i’m not sure if it’s a connection problem or something else, just a thought - i did over a hundred cards yesterday but it only saved 20 or so, and i’m doing the same cards again this morning. sorry if this is a duplicate.