bug#25245: Prettify-symbols-mode not working

[Alex Branham]

Hello -

I can't seem to get prettify symbols mode to work correctly. In my .emacs I 
have (global-prettify-symbols-mode). According to the auctex manual, that 
should be enough, right? However, when I open a tex file, nothing is prettified.

Weirdly, if I call M-x LaTeX-mode, then prettification works. Up until I save 
the file C-x C-s, when everything un-prettifies again. I can get the same 
behavior by calling M-x prettify-symbols-mode twice. 

I'm using
Emacs version 25.1.1
Auctex version 11.89.7

Any help is appreciated.
Alex