it all started simply enough with those two words
"I wish..."
Jon knew he could do better and started making a wish. but then wondered WHY is he undoing it anyways, it has a time limit to begin with. Did it make him nervous? did it somehow feel like he failed at getting the results he wanted? could it be an act of fate? an act of divine whim? Maybe the magic tugged at him subconsciously? Maybe it was some divine whim pulling him with its holy guiding hand? Maybe the universe was a patchwork compilation of the imput of many divine forces some of which homophobily try and stomp out some options after creating them lest anyone seek to explore them? Nah, this was getting too silly even for Jon to beleive. But still he started making a wish and had to finish it. and finish it he did.
... that my parents personality traits are swapped forever."
He said that and smiled. It'd be fun seeing his dads macho views typical of men his age be replaced by a more feminine demeanor.