Probably this isn't a bug and it only happens to me, but some jewelry and leatherworking recipes appear as collected (by a character that has only farm profs: herb and mine).

Is this a bug? If this is only mine, how can I solve it?

@Volthumn Check the settings for AllTheThings under > Sync tab. There should be a window of all characters cached in ATT data and you may right click to delete characters which have incorrect data showing.