Yesterday a smart contract bug in ICX ERC-20 tokens was found. A != instead of an ==.
Yeah, you heard right, only one character. "!" instead of "=".
THIS almost caused Icons blockchain to fail. This check was supposed to make sure the contract is enforcing a wallet address that IS equal to another one. But by mistake it was doing just the opposite of that. This error was allowing anyone except the smart contract creator to enable or disable token transfers for everyone.
Luckily the team behind Icon became aware of the issue and fixed it ASAP that same day, as obviously it was as easy as changing just a single character. However this made some users wonder if a cryptocurrency as big as Icon (more than $750 million USD market cap) doesn't have any developer checking the code for errors and supervising the code before implementing it.