Check your unsold/ended page. Especially if you use 'Sell Similar' rather than 'Relist'. It's only happening on Sell Similar. I've done 4 tests this morning, so it's a thing.. on my page anyway.
Do I have this wrong? Did Sell Similar from the Unsold, never remove the unsold listing from the list? I've always used a mixture of sell similar & relist but never noticed before. I am being DOH?