Does DIY ceramic pizza stone block oven heat from lower element?

[Dennis S]

I have a 16" unglazed tile on the lower rack. Someone said they heard Chris Kimball say it blocked the heat from the bottom element and left a "cold" spot in the center of the oven. Does this make sense? When I cook a pizza I put it on a flat round pizza pan on top of the stone. I leave the stone there for all other baking.