Office 32-bit vs Office 64-bit issue

I've run in to a strange issue that I'm not finding a solution for. I have four employees who are working on spreadsheets. File A and File B track information from two different teams. File C pulls data from A and B, then displays it all together. The files are located in the same directory on a server, so no one is using copies of the files. Three of the guys have no issues. One guy does, where File C shows #VALUE in the linked cells.

I've narrowed it down to the "bitness" of the Office version, all 2013. The guy with the issues is running 64-bit. The other three are running 32-bit. So, is there a security setting or something else in 64-bit that would prevent these linked cells from loading? I can find no other difference, even down to the permissions of the users on the folder.

This from Microsoft TechNet may help:

64-bit editions of Office 2013...
...As more and more personal computers run 64-bit versions of Windows, it’s tempting to deploy the 64-bit version of Office 2013 to match. One benefit is that 64-bit Office allows users to work with larger sets of Excel and Project data. But, there are compatibility drawbacks for those users because Office add-ins and solutions might not work. That’s why 32-bit Office 2013 is recommended for most users.

https://technet.microsoft.com/en-us/.../ee681792.aspx

I was assuming that wouldn't be the issue, as no add-ons or third-party plug-ins are involved. These are simple formulas to link cells from the other documents.