I went through my cards to make up sets and found that every base card #84 has an imperfection just under the number on each card! Has anyone else noticed this?

Yeah, mine is too. By the looks of it, it is a blemish on the printing plate and is probably on every #84 unless the set had a second run and someone cared enough to do a touch up. However, I wouldn't hold your breath on that one.

Thanks for your reply so much for quality control!