I've been having this problem as well.
My site is amadorvalleyhs.org
Here is what I can add to the conversation:
I’ve updated my style.css file and the updates aren’t being reflected.
When I use Firebug, the changes are not apparent. However, when I’m in WP’s editor, all of the changes are there.
One possibility that I have seen in other posts is that the problem could be linked to my host’s Page Speed Optimization setting. I’ve disabled it for now but the problem is still there.
I am using W3 Total Cache and when it is deactivated the changes I’ve made are there–the site looks the way I want it to…SO the problem seems to be with my configuration of W3 Total Cache.
Any recommendations?
My site is amadorvalleyhs.org
Thank you! Erik