I've tried burning a few Blu-Ray movie images using my portable Samsung Blu-Ray burner SE-506, using Apple's USB-C to USB adapter. The behaviour is different compared to my previous (sold) MacBook Pro. The Blu-Ray LED does not flicker continuously — it blinks in fits and starts, and of the three discs I've tried so far, none has verified on read correctly, and has been ejected prematurely. I've tried writing at 4x and 2x speed with the same results. Any ideas?