Color Overlay color not matching

[Spetzy]

I've been using layer styles for a while no problem and frequently use Color Overlay, but today outa no where it started to bug out?I'm trying to make a text check mark object to a bright green but its showing up as a much duller color. I've also tried different blend modes with no luck. Anyone else ever experienced this or know whats casuing it? 

[D Fosse]

This looks like a CMYK document, in which case it's out of gamut.