Been doing it for years on bone, ivory and antler for jewelry work. No problems. Maybe my experience is different than yours.Don't ever use bleach on antler or bone!! It strips calcium away and never can be replaced and becomes chalky. Use soap and peroxide first then paint. Stain is hard to control. So if that is the method go very light coats, once it is too dark you have to start all over. Paint is easier to control and if too dark it can be whiped back off before it is dry, in my experience.
Been doing it for years on bone, ivory and antler for jewelry work. No problems. Maybe my experience is different than yours.