Atlas edge issue

Hey everyone - I’m having an issue with a few atlases I’m trying to use. I’ve seen these use in tutorials so I know the textures are good - but when I use them I get what kind of looks like an opacity/antialiasing issue around the edges.

Am I missing something in my material settings? Maybe I’m not using the correct compression settings for my opacity/translucence maps? I’m at a bit of a loss and I can’t find any answers online - any help would be appreciated!

Can you please put a picture of the opacity mask used? Cheers