Sadly I didn't hear anything about the older frames. Is it the MK1 or MK2? Haven't seen anyone with a DC on a MK1 Capra. But doesn't mean it doesn't work. A lot of people put DCs on their Trailbikes because of the nice steering stiffness. But a frame eon't crack with a DC just from normal trail riding. Mostly bigger jumps, hits and drops force the frame to crack. The only thing I heard in terms of frame Problems was the early versions of the MK2 Capras chainstay that cracked on a drain port.
Hey there, I had some conversations with some people who put a DC fork on ab AL Capra. Either a FOX 40 or RS Boxxer. For Frames from 2019 and up it seems to work without problems. Just be sure to not change the geometry too much, so maybe you have to reduce the forks travel a bit.