Coinstar Rejecting Copper Lincolns?

I had recently bought a bag of $50 in cents from my credit union's coin counting machine to see what I could find. I thought I had sorted out all of the copper before taking to a CoinStar machine to turn my undesirables into an Amazon gift card.

I had checked the reject tray before starting and noticed nothing. At the end, there were a handful of cents leftover, most of which were 1982 and earlier coins I apparently missed in my original search.

I've heard of coin-counting machines being configured to reject silver (in fact, a gentlemen at the credit union said that their machine rejects silver). Odd that they'd be configured to reject copper, especially a CoinStar machine.