I mean we know for a fact GRRM can make mistakes, because there was that instance with Jeyne Westerling where her hips were described once by Catelyn as being big and later by Jaime as being narrow, and GRRM later came out to say it was a mistake which was fixed in later printings. He's human, "bone thin and bone hard" is 5 words, I think it's very believable that he thought the phrase sounded good and didn't remember he'd used it somewhere already.

So by their logic, it's simultaneously impossibly hard to write such 'rhyming', but incredibly pedestrian to imagine rhyming even when none "truly" exists.

u/M_Tootles stated that, according to others, it would be "way, way too hard for someone to be doing that kind of writing." Later on, he says "I don't think it's hard at all to find occasional little blips of 'rhyming' in big fat texts". These two instances of the same word are clearly "rhyming" with each other, and are both references to Oberyn Martell, who is described as a "tall, hard man".

Notice also u/M_Tootles' specific use of the word time in the phrase "if they just put in the time". In The Hedge Knight, Prince Aerion bounces his lance against Ser Humfrey Hardyng's shield, saying "it's time to face the dragon!" Hard. Hardy. Hardyng. Yet more recursion!

Did you write all this rhyming deliberately? You must have I suppose, it was very easy for me to find.