If you did, relax, there was not a glitch and they are probably all yours.
eBay started their new feedback program and an often overlooked aspect was that they would start counting positive feedbacks from repeat customers from sales made in different weeks.
It gave us boost of several hundred and was a pleasant surprise amidst all the other changes. My first reaction was "should we ask eBay if these are really ours?", but then the other half of my brain kicked in and it became clear.
Enjoy them. Savor them. The new system will reveal itself over the next few months and we may need the extra comfort.