mp3's in emails won't keep playing unless i'm in email - why?!

since I've updated to 9.2, I've noticed that I can't listen to mp3's sent via email unless I'm in the actual email that the mp3 is attached to. Before this update, I could download it, hit play, get out of the email/email app and still hear the music as i searched the web, texted, etc. Why's that? HELP PLEASE!

please don't recommend downloading it and saving it to itunes - i'm a recording artist & my engineer sends me some of my songs via email that i don't always download right away...