Floating name tags are not obscured when behind a wall/entity

In which version did this work as you expect it to?

I can't answer that question. It's even possible that this never worked correctly in BE

I see no reason for supposing that the way it works in JE is "correct" and BE is "incorrect." From your pictures, I'd say the Java implementation is more difficult to read and looks like a rendering bug where the block rendering is shading the name, as if the block were translucent.