For openers, let’s narrow something down. When you say bad smell, what do you mean? A lot of people have rotten egg smell. Is it that, or something else?
Is there a water softener being used on either side of the house? Unlikely, but best to ask.
I’m curious, too, about the type of anodes used. Magnesium and aluminum are what the industry uses for water heater anodes, and aluminum/zinc is the choice for odor issues. If someone put an Al/Zn anode in the first heater, but got confused and put aluminum in the Bradford White (they usually come with magnesium), then for sure you’d odor. I see people using the terms aluminum and aluminum/zinc interchangeably and they are not the same thing.