YouTube videos are defaulting to 360p even if other options are available. I am on an iMac 5K and I play a 5K video on YouTube and Firefox always defaults to 360p and never Auto. If I click Auto manually, it will play the video flawlessly in 5K since my Internet connection supports that. I have tried editing the media.mediasource variables in about:config but they were already set to true. I am using the HTML5 player and I'm on Firefox 45.0.1. A reset of Firefox didn't help and neither did starting in safe mode. I am out of options and I know there are addons to fix this, but this is something that should be happening by default. Please advise, thank you.