Bug? Maybe.

Umm, so I was doing little bit of minecrafting. You know the deal, singleplayer and all. BUT THEN, BOOM I HIT LEVEL 30! SO THEN I'M LIKE OOOHH HELLZ YEAH. What I do then, I craft a diamond sword. I get Looting 3 and Sharpness 4. Not bad, not bad. So then, after some time, I hit level 30 again and BOOM; ANOTHER SWORD WITH SHARPNESS 4 ONLY. I was disappointed so I was anviled the two sword together. I made an anvil and mixed the two swords together. Final result: Sharpness 5
Looting 3
I was happy with that.

But then here's the real deal. I was doing some building. Then I took my stone brick and placed it down by accident. I then scroll down to my sword while scrolling down to my pick. I notice that the sword was actually breaking the stone brick as if I was breaking a Glowstone Block. I don't know if this is a bug, I'd definitely like to know. I don't know if this has happened to anyone else :/

Let me know if it has.