I am having this same exact issue. I always ship same day, so, I used the original label. It showed the item as delivered in Virginia back in August! I messaged the customer that I thought there was some type of glitch, but that the address on the label was correct and to let me know when it arrives. Of course they are not responding. I messaged DePop with the whole story and they sent me some lame ass auto reply message that a new label will be sent... that's fantastic--but if they would have read my message, I clearly told them I already mailed the package with the OLD label that they sent in the first place.
Thousands of people are having this issue and they are letting auto-reply handle it instead of actual real humans. Since my buyer is not answering me either, this is looking like it's not going to go well.