Websites viewed with Symantec 12 are being altered

I work at AIIM and our website www.aiim.org is being altered when viewed on a MAC OSX with Symantec 12 installed. Our logout link turns into a button that hovers over our keyword search and our pdf files when someone goes to download them it starts up then hangs half way and does not load. What type of filtering does Norton run on sites that may cause these issues. Thanks for any help. I have screen shots if anyone would like me to send to see the changes that are happening. From what I gather this is only happening on MACs. As soon as I turn off Symantec the website works and looks correct.