Hi Mike,
We're having the exact same issue as you mention, but let me add more my case details from my investigation.
To find out if it's just her machine, I get my user to log in as her on other machines with Excel 2010, and the issue also comes up. So it's not just her machine, but rather her user-specific setting(s), which I don't know. And this means we can rule out machine-specific settings such as EPM Add-in's 'User Options' -> 'Automatic Refresh on Context Changes'and EPMXLClientPreference.XML as Charlie suspects. Thanks, anyway. ;-)
Another thing I've found is even though our users run on a mix of Excel 2010 and 2013, it seems to happen only 2010 and not 2013.
And it happens to her user in both QA and Production systems, so it's not system-specific, either.
I've looked into note 1908840 and applied VBA macro source code to our workbook and can confirm that it solves the problem, but that means the refresh occurs twice, just with one click, which we're not very happy with as it means more refresh time, so we're still searching for a better solution. The SAP note doesn't mention the actual cause of the problem, so it's not clear how to fix it.
By the way, we're on BPC 10.1 SP 4 on HANA.
I'll keep checking back this thread and provide the solution if I ever find one.