Also nonce misuse is a common failure mode among novices who might not understand what a nonce is supposed to be. People do all kinds of mistakes including using hardcoded static nonces. Its also fairly easy to come up with a bad protocol where someone can trick you into nonce reuse. Or there is a complicated error path that might involve a device going through reset where a nonce reuse might occur. Some of these are not so trivial to identify either.