Problem Solved...
We received a BOSCH 500 Series from my brother after he was having problems with it.
We noticed a BAD smell after a couple days left unattended and noticed water was at the upper level of the filter screens in the base. We tried vinegar and baking soda but no permanent solution.
I pulled out all the screens and found the stainless steel micro-screen cylinder shaped filter had a whitish coating on the inside (not seen earlier). It created a surface tension which held up to a couple cups of water that turned putrid from that whitish residue. We brushed that all clean, put it back together and now the pump clears all the water from the bottom of the dishwasher.
Also, I've read higher end BOSCH dishwashers now have a feature that pops the door open to allow drying out of the inside to reduce moisture in the warm insides which can promote bacterial growth.
So now we also flip down the filler door for Rinse Aid and that holds the door open just enough to allow for the drying out of the inside after a wash.
We've never have a problem since. Hope this helps...