Problem with #ifdef in GLSL

Hi! I’m having some very strange bug with GLSL…

i do, in a certain piece of code (works in all others)

#define SOMETHING

#ifdef SOMETHING

blabla

#else
bleble
#endif

but blabla is never compiled, bleble is compiled instead.
Is there any reason this may be happening? is there a limit on #defines on a shader source? or a known bug in nvidia gl driver?

seems it was a driver bug, newer version fixed it.