Big bug with sorting products in promotion price

[tomi]

Hi,
does anyone will know how to solve or to try to do it (eventually fudge)?
Presta Team changed it to improvement and I think it's serious bug.

When we have 8 products: 4 for $10/each and 4 for $20/each
One product for $20 with "specific_price" $5 ($20 - sale $15). Settings: "Product on page" is 2 then we have 4 pages and sorting is "from lowest".
Product with price $5 should be first on first page but now that product is on page 3 and first 4 products for $10 are on first 2 pages.
Because presta read normal price and should use "specific_price" if is defined.
"Specific_price" is sorted only on page which we see and normal price is sorted on whole shop.