It looks like some form of debris caused a strikethrough. I have a 2005-S KS Silver Proof SQ with a small strikethrough near LIBERTY. Granted, these proof coins are processed by hand so you would think that they would be removed at the Mint, but oversights do occur. By the way, this strikethrough was found in an order of four 2005-S Silver Proof sets that also produced my 2005-S KS Silver Proof, NGC PF70UCAM, FS-901 Die Dent. Chris
