As best I can tell, this is due to the only two criterion for Monster Eggs being the strings "mon" and "egg", both of which are found in "Diamond_Leggings". Please tighten up the searching criteria for this so we don't get this kind of issue in the future.

your report makes it sound like searching for diamond leggings returns monster eggs. Is this what is happening or the reverse?

actually, the criteria for monster eggs, are 'spaw' and 'egg' as they are actually called Spawn Eggs
http://www.minecraftwiki.net/wiki/Spawn_Eggs

Please tighten up your report so we don't get this kind of issue in the future.

Monster_Eggs is the enumerated name for Silverfish Stone. Confirming your statement, searching for "Diamond_Leggings" returns Material.MONSTER_EGGS (silverfish stone).

fixed.