Edited Issue: tab default style not displaying correctly [20576]

I have a tabs control on my page and the tab headers and not diplaying correctly. I am using the default stylesheet (I'm not overwritting) and the tabs appear to have a strip taken out of the bottom of each tab like a white block overlays the bottom of the text part of the tab and the left edge image. The right image is complete on each tab.

Does anyone know what could be doing this and how I can correct it? I'd like to use the defaults if possible.