I never had one break, but years ago some of us were shooting together and I saw one break. The gun was a near new series 70. Suddenly, the owner stopped shooting, with a confused look on his face, and I saw the slide on his pistol was open about half way. We examined the pistol and discovered the collet segment with the lug that locks the bushing into the slide had broken. The recoil spring, plug and broken collet bushing went down range.
That being said, a Gold Cup I bought new back in the mid '70s is still going strong with the original collet bushing.
Many shooters did replace the collet bushing with a solid Colt drop-in bushing. I sometimes did too. The collet bushing really did provide the accuracy advantage of a fitted match bushing. I found that accuracy did deteriorate when factory drop-in solid bushings were substituted for the collet. Fitting a match bushing restored factory collet bushing accuracy.