So I came to the very unexpected finding today that there is dust under the screen of my 9930. I had this issue constantly with my 8330 but I wasn't surprised because the screen plastic had a decent amount of space between it and the back. I didn't think that issue would arise with the 9930 since the screen is pressed in. I'd imagine disassembly isn't as easy as the 8330 was so my question is what's the solution for this disturbing inconvenience?
The screen is sealed, so something happened to yours. Contact your carrier for a replacement or to RIM so they fix it. I had this problem with my first 9900 the glass was lifting, and T-Mobile sent me a another 9900.