Looks like eBay's still attempting DCC despite being in the process of transitioning away from PayPal:
Fortunately, unlike in the past, it was relatively easy to opt out by pulling up the currency options box under payment options:

According to xe.com €42 converts to $47.41, so eBay's conversion is a bit more than the 3% they claim. But we'll see what rate Chase uses in any case.