Yeah.... I forgot. The OR-ed terms need an outer set of parenthesis too (and I should have left the Media Type rule outside them entirely).
[Media Type]=[Audio] (([Rating]=>=4 [Genre]=[Acoustic],[Vocal],[New Age]) or playlistid==1051196379) ~sort=Random
The idea is that you want to surround the entire OR part in parenthesis so that it combines into a single term. So, in this case:
* [Media Type]=[Audio]: applies to the whole thing*
then...
* (term 2 or term 3) where
** term 2 is ([Rating]=>=4 [Genre]=[Acoustic],[Vocal],[New Age]): the inner parenthesis make this into a single term
** term 3 is playlistid==1051196379: parenthesis aren't required here because it is already a single term
then...
* modifier ~sort applies to the whole thing
Sorry I messed it up. I should have tested it, but I don't have a matching PlaylistID, of course. I did test this one and just substituted one of my own lists, so I'm sure this version works right. You can do it the way you did it with three lists, but Playlist references can be fragile, and I'd combine it into a single list if possible.
* Having this as a "global rule" is really unnecessary since your manual list assuredly only contains audio files, but you really do want the whole list to be audio, so why not do it right.