Maybe I'm misunderstanding how this "Scrap Detector" skill works or I'm encountering a bug with it, since I'm unable to get it to proc when digging multiple stacks worth of sand. It's supposed to be a 4% chance when your character breaks a Sand block, like digging it with a shovel? My character has Collecting > Digging > Scrap Detector 2/2 and Scrap Specialist 1/2 on Xskills 0.8.5 on VS v1.19.8, and haven't received any procs after hundreds of attempts, listed below:
3 stacks of Andesite Sand with a Tin Bronze Shovel
3 stacks Andesite Sand with a Flint Shovel
1 stack of Andesite Sand with "Bare Hands" (holding no item)