Thats the same in a lot of brokers. Ameritrade shows the old symbol seems like forever sometimes. Guess it depends on the play and what broker but they all do funny things at times. I still have R/S's that havent changed in a month or two in Zecco.
As a matter of fact, US, your the one that enlightened me about these "back-door reverse splits" quite some time ago. SHO chat I believe. A year and a half ago maybe.