Pickled garlic never quite right?

I followed the recipe for soy pickled garlic from Korean bapsang for the second time and something seems to keep going wrong each time I make it and I can’t determine what. After following the instructions explicitly the garlic pretty much tastes like regular raw garlic, has had no change in texture, and this time gotten a bunch of dark spots that weren’t present during my first try (I use pre peeled garlic I got at lotte market). Has anyone else tried this recipe or similar and had this kind of outcome? Are the black spots safe to eat? What could cause it to not have much of any flavor change despite sitting in the soy brine for two weeks before tasting? I LOVE the pickled garlic I get at restaurants and wish I could figure out how to duplicate it!