I have a B7O as well. I have the same symptoms you have but I didn't notice it until you asked. I don't think it is worth returning JUST for this. My B5O has a speaker issue, light bleed and a clicky/soft case by the volume buttons. I like he stiffer buttons as I did an accidental factory reset with the older softer buttons. I don't think that they will stick or break and if they do you still have a warranty.