Reporting formatting on a cell with multiple colours fails in Excel 2013. The cell contains black and red. Where the word 'red' is coloured red.

Steps to reproduce:

• Using Excel 2013 open up testCaseRedAndBlack.xlsx.txt (after removing the .txt part of the filename)
• Move to cell A1 and press NVDA+F to report the formatting.
• Notice an error sound when enter is pressed.

Expected behavior:

The formatting of the cell should be reported.

Actual behavior:

An error sound, no formatting reported. The following log entry:

Input: kb(desktop):NVDA+f
ERROR - scriptHandler.executeScript (14:52:04.819):
error executing script: <bound method GlobalCommands.script_reportFormatting of <globalCommands.GlobalCommands object at 0x04D78B70>> with gesture u'NVDA+f'
Traceback (most recent call last):
  File "scriptHandler.pyc", line 187, in executeScript
  File "globalCommands.pyc", line 1295, in script_reportFormatting
  File "textInfos\offsets.pyc", line 392, in getTextWithFields
  File "NVDAObjects\window\excel.pyc", line 977, in _getFormatFieldAndOffsets
TypeError: int() argument must be a string or a number, not 'NoneType'

System configuration:

NVDA version: next-14098,66f26bb2

NVDA Installed or portable: Installed

Windows version:
Windows 10 Version 1607 Build 14393.1198

Name and version of other software in use when reproducing the issue:
Microsoft office Excel 2013