Hero's played percentage breaks when you reset account.
If you reset your account stats the number of times a hero has been played does not and you get incorrect played% for your heros (currently I have above 100% for all my played heroes).
As well as this, they're also still broken for everyone afaik(mine are). Because playing both ranked and public games screws them up, something which was supposed to be fixed with the retail stats wipe.
Borken for me too sometimes, when switching between public and ranked. I didn't purchase a stats reset(reported this as a separate issue though)