I've had 2 crashes with the new preview build. Can't upload the report here so here is what it says.
Current thread (0x15b26400): JavaThread "JavaFX Application Thread" [_thread_in_native, id=8068, stack(0x169e0000,0x16a30000)]
siginfo: ExceptionCode=0xc0000005, writing address 0xbbadbeef...