Hi there,
I have the same problem with EPM Add-In causing Excel ribbons to be come unresponsive. I can pull menu down but when hover my mouse over a submenu, it won't highlight the submenu and clicking on submenu doesn't get it to respond either.
I know the thread is quite old, but the issue is still there in my system even now that I have the latest updates of MS Excel 2013 as well as EPM Add-In version 10 SP 24 Level 1.
I've contacted SAP regarding these incompatibility issues with MS Excel 2013 and the outcome was they said to wait for Microsoft to fix those issues.
They believe, as per SAP Note 2219713, it's to do with using freeze pane in the input form along with having updated MS Excel patch KB3085502, but MS came back with a few more updates after that.
I've also tried unfreezing pane in my template, but it doesn't help fix the issue either.
I've even tries using EPM Add-In's native refresh button as mentioned by OP, instead of my custom button with some VB code behind it, and I still get this problem.
As for YH Seo's suggestions, in my case, my template doesn't have any VB code in AFTER_REFRESH or WORKBOOK_OPEN at all, but the issue is still there.
A small tip for when Excel becomes unresponsive, if you really have to continue working, e.g., at least to make a few changes and save data, you can use keyboard shortcuts, those still work -- it's just the mouse that won't be responded to by Excel.
So, as of now 1/27/16, I still call it unresolved.