During Steam sales, like the current week-long deals, there are some games that appear twice or even thrice.
Currently, there are three entries for "Rising Storm Game Of The Year Edition" that all show the same store page for me.
I assume it's somehow connected to different region settings, since (as far as I can remember) everytime I inspect those games they show a notice for Low Violence or related things.
Best Answer
It appears 3 times because there are 3 different "deals" related to the game.
There are a number of other games that have multiple entries on the sale list as well for similar reasons. As an extreme example, the learning game Influent is listed 18 times, once for every available base language.
Why is it listed multiple times when they all link to the same store page though I can't answer, as it doesn't make sense to me either.