This seems like more of a problem with parsers not following the spec. It's a simple spec, but so strict and restrictive that it's a bit of a pain to give to humans, and small extensions (like comments) are immensely useful for its (ab)uses as configuration "DSL"s. And some edges like that the string format isn't specified - that's (basically) fine, it's not a connection-negotiation protocol.

So JSON parsers tend to implement some weird, unspecified, inconsistent superset of JSON. I haven't encountered one yet that fails to parse valid JSON though. That doesn't seem to imply that parsing JSON is a minefield. Only that parsing human input, nicely, is a minefield. No spec avoids the human ergonomic problem simply.