Hi. I'm running a very recent build of emacs from git revision 253d44b
(2015/01/08). I'm loading a very simple C file that has some enums
defined (attached). The enum elements all should have been rendered with

 font-lock-variable-name-face

However at startup with

 emacs -Q -nw

only some of the elements get this face; many have just the default
face. Pressing M-x changes things: some elements actually lose the
correct face. In general, using emacs tends to change what is or isn't
rendered properly. I'm attaching screenshots of the state at startup and
after M-x.

This is 100% reproducible on my end.