EMET 5.2 will not allow Adobe reader XI to open - Caller issue

I am using Windows 7 64 bit with Norton Internet security and EMET 5.2. A couple of days ago EMET started to block Adobe Reader XI with a Caller mitigation problem.

The only way I can open Adobe Reader is to uncheck CALLER for AcroRd32.exe in EMET configuration.

I contacted Microsoft Technet and they said this was a Norton issue and the only change to my system recently would be the regular Norton updates so it seems plausible. Full NIS and Malwarebytes scans were clear. (I only use Malwarebytes to scan, it is not normally active.)

Is this a recognised issue and is there anything I can do to fix the problem?