One of the most well known issues with the HTC EVO 4G's most recent OTA software update (version 3.70.651.1 released in December) is that it broke the phone's formerly functional audio streaming abilities. Even though there's been an easy fix for it (find it here) out for months, Sprint still hasn't pushed out an official update to correct the problem.
In fact, up until a few days ago, many EVO users didn't even know the streaming quality on their phones were affected. But thanks to an unprompted appearance of a notification alerting them to the issue that's been around since December, people are now taking the unsolicited advice and calling Sprint to get it fixed.
The "Streaming on Your HTC EVO Device" pop-up is believed to originate from Amazon, whose new Cloud Player service has been giving many EVOs network errors since its launch last week, though some possibly clueless reps at Sprint have been telling customers the notice actually comes from HTC. The original fix solves Cloud Player's problems, as you know, but Sprint will reportedly push a fix to your phone if you do as you're told and "let them know that you are having trouble streaming multimedia on the HTC EVO with software version 3.70.651.1."
So if you're still having streaming issues on your EVO and the old fix didn't work for you, then Sprint may be able to help.[Android Forums] Thanks, Doug!