I would guess the savings accounts just aren’t bringing in as much in deposits and there are more small accounts and higher operational costs than they planned for.
There’s been no indication at all that the savings accounts themselves are unprofitable. This article combined a journalistically negligent misquote from a single person at the internal announcement of the savings accounts with fuzzy numbers about previous provisions for future losses from the credit card. If they had any integrity, they’d just delete the whole article.