7d Red Flash on focus

every now and again (obviously not always) when the 7d hits its focus, i get the red flash in the viewfinder. i sometimes will deliberately focus on something way out of my subjects range and then back to see if i get the hit...

doesnt always happen but i do get the focus confirmation dot in the lower right corner of the vf and the camera will fire, but im curious about the inconsistent red flash...

this is a refurb with a warranty expiration coming up in another 3 weeks or so...

My recollection is that the manual calls it low light focus confirmation.
It only occurs when the ambient light is low or some other criteria I can't figure out.

5DIII does the same thing. Just get used to checking the green dot rather than a red focus square as per earlier cameras.

I think you can set Viewfinder Illumination to "Always," or is this a different feature?

C.Fn III -8.

Yes, it's so you can see the focus point even in low light.