Only the original size and price on purchase.

Hi, thank you for the great plugin. I have a small problem. When I’m trying to add recently uploaded in media library items to Sell media item, the photo is there, but on purchase I see only the original size. I have one prize group with only three sizes. When I’m adding the photo I choose the prise group.
I uploaded a new photo and there everything seams OK, but why adding an existing item it doesn’t work the same way?
When I started to add uploaded photos today I added some without a problem and they show the sizes correctly, but after 2-3 photos every other didn’t show the sizes anymore, just the original.
Can this be a bug or I’m doing something wrong.
You can see my site here.

https://www.ads-software.com/plugins/sell-media/