So the vault is bugged or something

I opened the vault yesterday and there was 3 skins for kiriko and 2 for Moira (keep in mind I only play mercy rarely anything else) , today there's a ramatra skin, Ana, Widow, etc. Why did it change for me? Is it normal? I did contact support 2 times now they told me it changes every day and it's not supposed to be with skins for your most played heroes (also they put a link about the vault where it says the vault puts skins based on your account xD) .