Okay, I just gotta show this thing off. I won some mint sets (4-70's, 4-71's, & 2-74's) in an auction. I was mainly after the 70's but this lot surprised me. Of the 10 sets, 6 of them have at least one error/variety in them with a couple having multiples. I couldn't believe this passed QC to find its way into the cello. I'm thinking it's a strike through but could it be a defective planchet , a lamination issue, or something else entirely? So, I will welcome everyone's input as to what your take is on this...
I think it may be a strikethrough, too! @Double Die , why should you be surprised to find it in a Mint Set? It's not like they hand-inspect each coin, and the coins are placed "heads up" on the cello. They all come out of the same bins that hold the circulated coins. Take a look at this 2005-S KS Silver Proof SQ. You might wonder how it slipped by inspection, but then again, the SQ's are placed in the plastic case with the reverse facing up, not the obverse. ~ Chris
It passed QC with lot sampling and all the other control features that any high volume manufacturer would use. If they had tighter inspections that penny might cost 10 cents or more to make.
That one particular person just spent hours assembling those sets.. They just thought.. "Meh, whatever"