I'm on macOS Sierra, Xcode 8, and get crashes whenever I try to Simulate Background Fetch on an actual iOS 10 device. This does NOT occur when using the simulator. This occurs in all projects, including those freshly created.
0x18cfec164 <+0>: movn x16, #0x1e
0x18cfec168 <+4>: svc #0x80
-> 0x18cfec16c <+8>: ret (Thread 1: signal SIGSTOP)
You aren't alone - I'm encountering this as well. Really annoying. I've just filed a bug.