The overprinting in black does come off. A lot of handling will do it. The presence of some solvents will make it worse, some hand creams for instance. Deet based insect repellant is notorious, removing print from carrier bags. Is this after public handling on a hot summer day?
Resisting involves a seal over the top, artists suppliers sell a spray to seal watercolours that might help. The legislation says it must be legible and indelible but not to any specific standards. If you print your own, another label over the top is quickest solution.