Yup, it’s really quite weird.
Found an Alpina B10 3.3. Sold for £9k in may last year, then £12.5k a couple months ago, and now on sale for £17k!
https://www.carandclassic.com/auctions/2000-bmw-alpina-b10-33-manual-e39-nAJJm4
https://www.carandclassic.com/car/C1690606
Now there’s a rather ropey one being sold on ebay, with a current bid of 6k. No doubt it’ll sell for more than that one did last year, with almost double the mileage and a Cat D!