My thrift store croissant mold wasted $12 and 6 hours of my Sunday

Found this cute vintage croissant mold at a flea market in Portland for $12 and thought it'd be a fun kitchen gadget. Tried it three times last weekend with my usual dough recipe, and every single croissant came out flat and lumpy, like sad pancakes with ridges. The mold was too shallow and the ridges grabbed the dough so bad I had to use a knife to pry them out, which wrecked the layers completely. I finally looked it up and turns out it's actually a butter shaping tool, not a croissant mold, so I was using it totally wrong the whole time. Lost about 6 hours total between mixing, proofing, and cleaning melted dough out of the grooves. Has anyone else bought a mystery baking tool and only learned what it really was after a total fail?