sorry, i misunderstanded your meaning right now,
on android, when the app enters the badkground, the texture data would lose, so the engine has cashed the texture infomation by default.
please make sure that the macro CC_ENABLE_CACHE_TEXTTURE_DATA is not 0.
for more information, you could refer to CCTextureCache,
if you could debug it, and provide more information, it will be appreciated,
btw, what is the machine you are using?