2004 Silver Maple Leaf 5 Coin Set

Have a question for you experts.
I collect Silver Maple Leafs. I really enjoy them and have more than thirty of them. Different dates and privys. Awhile back I received the 2004 five coin set with the mint privy mark. They were in the leather box and each one was in the mint plastic round container. The 1oz, 1/2oz and 1/4oz had some dark ink-blue spots on the high areas of both the obverse and reverse of the coin. My local coin dealer didn't know what it was. It was not toning. There was no soft blending of the color into the silver and they were minted in 2004 so I can't imagine they would have started to tone so soon. It looks like blue ink and the spots have defined edges.
I sent them back and recently bought a different set from a different individual. That set has the same ink-blue spots on them. The first set was #'d 00532 the 2nd set was #'d 16365. At first I thought it might be PVC contamination but the plastic containers are hard plastic and, I assume, from the mint. I called the mint in Canada and they didn't have a clue. They just said it wouldn't have left the mint in that condition.
Anyway, does anyone have any ideas or know what the deal is. If anyone else has a set - you might take a look at them and see if yours has the same thing. I'm sending this other set back.
Would appreciate any info. Thanks.