I have not been able to reproduce this issue since the first and only occurrence. But when I pressed next to skip a song the controls disappeared and were replaced by a grey box. I pressed back to go to the main interface and then maximized the current song and the controls reappeared. I was able to get a screenshot of the controls disappearing.
This was probably due to an exception thrown due to a failed network request when rendering the artist image, and should be fixed with the next update :)
I have not been able to reproduce this issue since the first and only occurrence. But when I pressed next to skip a song the controls disappeared and were replaced by a grey box. I pressed back to go to the main interface and then maximized the current song and the controls reappeared. I was able to get a screenshot of the controls disappearing.