Me too I struggling with YouTube issue.
Every time I try to switch resolution of a video until it starts.
What I believe is That advertising video are freezing the playback because when I reboot it works and after some videos it starts stopping video.. Normally you tube let you see first video without advertising
For the 3498328903809th time, this is happening at randoms MiBox. Just check in reddit and in previous page, there are some miBox users that are having this issue.
The fact that you're not having this issue doesnt mean that it doesnt exist or there are a lot of users lying.