there are a bunch of cards that don't like anonymous billpays. discover is one. capital one another. some citicards.
other cards don't like cycling credit limits. throttling available credit after payment mitigates their perceived risk for both of those actions.
some banks have been known to close accounts for excessive bill pays.
the credit limit will eventually free up, but it just isn't worth it as much anymore provided you can find other liquidation avenues.