I have the exact same issue in our Swift 3 project. Would love to hear how to fix this!
Our Project is Swift 3 and has some frameworks that are Objective-C and got the same issue where the Backtrace isn't getting symbolicated.
I notice this error in the System.log
Nov 17 15:45:50 minimac016sMini Xcode: Failed to read draft status extended attribute for document at: /89484. No such file or directory Nov 17 15:45:50 minimac016sMini filecoordinationd: NSFileCoordinator only handles URLs that use the file: scheme. This one does not: x-xcode-debug-memory-graph://7fd1ba8b5db0/89484
Some good news, this seems to be fixed in 8.2 beta 2
Also have this issue. Not sure how to proceed.