Got a bye to ranked bracket finals. Played two matches. As the third was about to start, instead the screen went black for a while, until a popup saying the opponent disconnected came up. At that point I immediately returned back to practice mode without displaying the post-match screen, had not gained any stars and had not automatically rejoined queue.
Log file, set to expire from pastebin after a month
Windows 10 Home
i7-6700, 16 GB, GTX 980