Where I live, it spontaneously generates Jonty as a nn, which is enough to put any thinking parent off it for life.
Apart from that, it also attracts bizarre spelling mistakes: I had a Jonathan colleague once who collected them. He'd been Jonathen, Johnathan, Jonathin (when he was a dancer and anorexic!) and Jonathon - like a road race, he said glumly. Oh, and Johnnythan!
I always see Jonathans as weak and weedy and lacking initiative, which is no doubt unfair. But I vastly prefer John.