My collection currently stands at 29k photos + 7k videos = ~36k assets. I've deleted all existing thumbnails and started a new job to recreate all of them, which has so far generated 13k and lists 76k as "waiting".
My interpretation of the thumbnail settings is that each asset gets a small and a large thumbnail, which leads me to expect ~72k thumbnails in total.
However, the waiting count keeps increasing even as more thumbnails are being generated. Is this working as intended?