It's not marking games appropriately that one already owns. Heroes Hour for example. I own it already but it's not being marked on the sale front page saying I already have this product.

Not to mention if you click the game that's on the sale at the time, it goes to the game page and shows that you don't own it in your library.

HOWEVER, if you search it in the search bar, there are TWO Heroes Hour games. One owned and the other not. Yet it's the same game. Not a different edition.

This needs to be fixed!

This is being discussed in the Insomnia News thread: summer_sale_special_start_of_insomnia

There are different theories, but part of it may be because the Insomnia games appear to be separated out as only a temporary store page to mark out the Insomnia games/keys for some GOG internal purpose. However it is also providing a way to look up the next-in-list as discussed in the Insomnia tracking thread: summer_sale_2023_insomnia_game_discounts