I add mood tags in mediamonkey which I normaly read in mp3tag, for mp3s I use therefore "COMMENT MUSICMATCH_MOOD"
But for flacs theres a strange behaviour: Only with "MOOD" in the tag panel im able to read my MM tags, if I want to use it in the columns or for functions %mood% doesn't affect anymore.
The backslashes look to me as though you have multi-value fields.
You would need $meta_sep(mood,\) to show them all in the column
So it could be that you have a space as first character in the first field ...