Custom cell formatting crashing Excel 2013

Hi all,

I have a user who's recently been upgraded from Excel 2007 to Excel 2013 (aka Office 365). He has a spreadsheet that he worked with regularly in 2007, that has the following custom cell format:

[=1]"EBITA";[=0]"EBITDA"

With Office 2007 the cell would display the corresponding text, based on a cell value of 0 or 1. Since moving to Excel 2013, this custom format keeps crashing Excel. With further testing, I've discovered that this only crashes where upper-case text values are defined. In other words, if I change "EBITA" and "EBITDA" to "Ebita" and "Ebitda", then the formatting works as expected (unfortunately, not an acceptable fix for the user in question).

Whilst I thought it might be caused by a corrupt spreadsheet or an Excel plug-in on the users machine, I'm able to replicate the behaviour on a completely different Excel 2013 install, when running in safe mode on a new spreadsheet. Anything with a custom upper-case text, seems to crash Excel (e.g. [=1]"PAID";[=0]"NOTPAID" will crash, but [=1]"Paid";[=0]"Notpaid" will work).

Any thoughts? In both cases Excel has been updated to the latest release (Excel 2013 (15.0.4719.10000) MSO (15.0.4719.1000) - 32-bit).

Many thanks,

Rob

PS: The following is recorded in the Application event logs:
Event 1000:
Faulting application name: EXCEL.EXE, version: 15.0.4719.1000, time stamp: 0x552cf4af
Faulting module name: EXCEL.EXE, version: 15.0.4719.1000, time stamp: 0x552cf4af
Exception code: 0xc0000005
Fault offset: 0x00187f46
Faulting process ID: 0x1ab8
Faulting application start time: 0x01d0acff97697bf4
Faulting application path: C:\Program Files\Microsoft Office 15\Root\Office15\EXCEL.EXE
Faulting module path: C:\Program Files\Microsoft Office 15\Root\Office15\EXCEL.EXE
Report ID: e1cf290f-18f2-11e5-bec5-f0def1777ee5
Faulting package full name:
Faulting package-relative application ID: