Incorrect Dates in History?

Something is wrong with the History tab. This NFT sold most of its tokens in late April. I followed the sale carefully in real time. The history was correct. I know that there’s often a delay between the “Purchase” and the “Transfer”, but it’s usually negligible, as it was in this case.

But I just looked at it again today, and the Purchase dates have been moved a month later, nearly all at the same time. Was this a weird glitch? For reference, here’s the NFT. Notice the odd Purchase timestamps. (Feel free to buy the remaining two! Just kidding. But not really.)