Could be a couple of things...
If your new bottle spent any time in your car or any other place where temps were above 110 F, the heat killed the bacteria. If you didn't let it get hot, the vendor may have.It's also possible that your tank vent has a partial blockage that's reduced the amount of air that can get into the tank.Or, any household chemical cleaning products used to clean the toilet may have killed it.There's no reason whatever to avoid putting solid waste in the tank...and every reason TO put solids in the tank. The absence of solids doesn't prevent odor (as you alredy know)...and solids in the tank doesn't increase odor, either. Odor is solely a result of anaerobic conditions, regardless of the material in the tank. Urine does not have any bacteria in it...neither does the flush water if you're using fresh water instead of sea water. Solid waste does...and bacteria is needed for natural breakdown to work as it should. So flushing solids actually HELPS your tank work as it should. But the only bacteria in your tank is the bacteria in K.O. It's not getting any help from nature at all. I don't think that's the reason for your odor...just seemed like a good time to mention that avoiding flushing solids is based on a totally misguided idea that has no basis in fact whatever.