Eh, I could be doing some real work but this is more amusing....
Anyway, did a quick check and opened all 3 browsers in both modes:
Safari is new site
Safari in Private Window is new site
Chrome is new site
Chrome Incognito is old site
Firefox is old site
Firefox Private Window is new site
How's that for consistent?
P.S. and yes, that means the AC agent I spoke with was using the old site and yet, the new one is available on Firefox too.