Update: AT&T just sent us their official word on the matter -- and they also told us it has nothing to do with MMS or 850. Check it out after the break.
This week, AT&T and RIM discovered an issue in the most recent software update for the BlackBerry Bold, only affecting a small number of customers in a handful of markets. The issue may create call performance problems that can be corrected. We encourage any customer who believes they are experiencing this problem after installing the most recent update to call customer care for help.
We are working to fix this problem as soon as possible. In the meantime, if a customer encounters issues with the software, they should contact customer care.
Customers who have the b508 Bold Maintenance Release who already have Visual Voicemail can continue to enjoy its benefits. Other interested customers will be able to get Visual Voicemail once the new software build becomes available.