Well, after suggesting I try this and that, this is the response I got from FTM:
"Unfortunately, because Family Tree Maker is utilizing the Safari web browser on your machine, this falls under a known issue that our developers are currently working on. Because Safari is not an officially supported web browser, some of the settings are conflicting with our software. This is something we're working to fix as quickly as possible. We're very sorry for the inconvenience, and would like to thank you for your patience."
Not sure what they mean by safari not being an "officially supported web browser" as this is what FTM for Mac relies on for ancestry.com web searches from within the FTM software. Ayway, lets hope a fix comes soon!