I had an O-ring fail/rupture on the caliper connector of my rear R785 after about 6000km while being somewhere in rural France. The bike shops there all had brake cables, non had the desired O-ring.
Had the same problem. Changed the caliber and its been flawless ever since then. I think the system can be made bulletproof by using any of the mtb calipers.
10,000 km on Shimano hydraulic with zero issues.