There's a timeout? Something is funny. I'd do a hard restart (force off, wait and then turn back on) while the car is running. If that does nothing then I'd reset the unit.
On my INA-W900BT (I know it is not yours but just for general ref) there is no timeout or screen blacking function. I do have an auto-hide feature for the on-screen music controls I can tun on or off but that's it. My head uint isn't great but I really feel for you guys with the MY10 Alpine.
2012 Lotus Evora - IPS, Nightfall Blue
2011 Jaguar XF-R - 510hp
2007 Jeep Grand Cherokee - Overland, Hemi (The Anti-Lotus)
Totalled: 2011 Lotus Evora 2+2 - Canyon Red Metallic
Sold: Saab 9-3C, MGB, Miata, Merc 560SEL, F-150, Civic, Saab 9-5SE, '05 Ford-GT, '69 Cad Sedan DeVille, Triumph Daytona 955i