Photoshop: Color shift, save for web with progressive turned on

Hi Photoshop world,

Question, I've been noticing a color shift on my NEC monitor (not on Mac monitors) with some images. Here's the breakdown:

Save for web - Optimized - include ICC profile (sRGB)
*Images appear saturated on NEC monitors, normal on Mac monitors

Save for web - Progressive (& Optimized) - include ICC profile (sRGB)
* images appear normal on NEC and Mac monitors

Any idea what's going on here? Does saving progressive alter the way that monitors read icc profiles?

Thanks for your input,

J