Both her Beret and deathslinger's jacket even have the same date and i still got my deathslinger jacket, But i'm missing my Beret!
I also have this same issue for both PC & PS4 (joekerthewizard)
In order to get the cosmetic you had to log in prior to 11am on the 2nd July, if you got the jacket but not the beret it's incredibly likely that you logged in after 11am EST on the 2nd.
I've logged on before then too, June 1st and before. I was saving bloodpoints up for the event.