Trading champions bug

I qued up to an aram and traded my talon I got for a taric someone gave up, after I clicked it my client went completely black and wouldnt show me anything but the timer after almost 20 seconds. I had the wrong runes and SS so i clicked were the x should be to exit out and not screw over my team. I dont know if this is a one time bug, but thought I'd bring it up.