Syntax highlighting randomly turns off

Question

I use syntastic and split windows heavily in my vim workflow. Lately, syntax highlighting will vanish, seemingly at random, in one of my windows, usually after opening a new split. This happens with the highlighting of js files, ruby files, even the highlighting on a vim documentation file opened through a :help command.

Running :syntax enable or :syntax sync from start will, rather than solving the problem, cause it to spread, so that all open windows lose syntax highlighting, rather than just the single window where the problem started.

I understand that this is may not be enough information to help me troubleshoot, but I don't even know where to begin to track down the root problem, since it happens sporadically -- once or twice a day I'd say, without any apparent pattern.

Any clues about what might be the cause, or how I should approach debugging the problem, would be helpful.

Additional Info About Plugins

find ~/.vim -type d -name syntax
/Users/jg/.vim/bundle/neosnippet.vim/syntax
/Users/jg/.vim/bundle/scss-syntax.vim/syntax
/Users/jg/.vim/bundle/tagbar/syntax
/Users/jg/.vim/bundle/unite.vim/syntax
/Users/jg/.vim/bundle/vim-coloresque/after/syntax
/Users/jg/.vim/bundle/vim-css-color/after/syntax
/Users/jg/.vim/bundle/vim-javascript-syntax/syntax
/Users/jg/.vim/bundle/vim-slim/syntax
/Users/jg/.vim/bundle/Vundle.vim/syntax
/Users/jg/.vim/syntax