Pinching a leader on a 60 foot oak in Austin backfired bad

Last spring I had this young live oak in a client's yard in Austin, maybe 20 years old, and the central leader was racing up way faster than the lateral branches. I decided to pinch it back about 8 feet to force more structure lower down. Thought I knew what I was doing since I'd read about it in a nursery manual. Six months later the tree pushed out three competing leaders instead of one strong one, all with weak crotch angles. Now I'm looking at a future cabling job or a potential split in a bad storm. My mentor saw it and just shook his head, said I should've left it alone until dormancy or just thinned the laterals instead. Has anyone else had a corrective prune totally blow up on them like this, especially with oaks in the south? What do you do when you're the one who caused the mess?