I've repaired a centre strut that had come away. You should be able to see pulled stitching if it has. 3 struts sounds very odd. Generally happens after a 'wash through'.
ie When you drop your kite and a wave hits it. Pressure is worse if you are still hanging onto bar. Hold a plastic garbage bag in the waves and you'll get an idea of how much force is in the smallest of shore dumps. It requires a simple yet careful stitch to repair it. Moti Levi has done some good work for me recently. Take care when pumping up as the kite sits upside down on the centre strut stitch, so if you're on an abrasive surface it can wear through the stitch and be a start point for a wash through