Voiceover inconsistency question

Hi everyone

I work as an accessibility professional and one of my jobs is making sure that our vendor is creating accessible sites for us. When I test a particular new site on VoiceOver with Safari, the reading order is way off and completely illogical. The strange thing is, on at least 2 other Macs (and I am about to try a third) the order reads great. I am having the same problem on Chrome. The flaw has to be my Mac or settings and not the code for the site. Since I am the primary tester of all of our sites, I need my system to function properly. I have tried the following: clearing all caches, upgrading browsers, upgrading my OS. Still it reads incorrectly. Any ideas on what the problem could be? Is my Mac haunted? ;)

Any ideas are welcome.

Thank you!