This is going to sound an obvious question but are you using it when you draw a card? You can only use it as long as the Drawn card is still up, before you apply it. And yes, only during battle, unfortunately (why make it like this anyways? I see no point and just a hindrance)

I ask because I haven't seen any bug with it and been using it normally ever since I got it. I'm lvl 60 now and still using it fine. Unless the hotfix broke it? I haven't been online ever since the maintenance.

You don't need Shuffle to be able to use Spread by the way.