whitespace-mode: Have to disable/re-enable to display trailing whitespace in sql-mode?

[Andrew Pennebaker]

I've configured Emacs to automatically use whitespace-mode for many modes,
and this usually works very well for displaying odd characters, such as
trailing whitespace.

However, in sql-mode, though whitespace-mode is automatically enabled, I
still have to disable and then re-enable whitespace-mode in order to
actually* **see* the visual indicators for trailing whitespace. This odd
little problem doesn't happen for most programming modes.

Is there something in my Emacs config I can improve to fix this problem?

https://github.com/mcandre/dotfiles/blob/master/.emacs

I'm using Emacs v24.5.1, from Homebrew, on Mac OS X 10.10.4 Yosemite.

-- 
Cheers,
Andrew