I have a number of Excel xlsx files which contain a Chart object configured with High-low Lines. The High-Low Lines render without issue when the Number Cache & String Cache exist in the file. A process updating the files removes the Number Cache and String Cache from the Chart Object. After this process has updated the files Excel no longer observes the High-Low Line configuration. I have verified that the files still contain the setting for the Chart to have High-Low Lines (<c:hiLowLines />). Excel does not recognize that the setting is set (not rendered when viewed or preserved in the file settings after saving in Excel). Excel does not present any errors and everything else works fine.
Reproduction of Issue:
1. Create an Excel Document containing a Chart Object with High-Low Lines enabled.
2. Manually edit the chart1.xml file (in the xlsx file), removing all the Number Cache and String Cache entries from the document (<c:numCache/>, <c:strCache/>).
3. Open the Document in Excel and view the Chart. It will not draw the High-Low Lines and if saved the file will no-longer contain the hiLowLines setting.
The issue has been confirmed in Excel 2010 and Excel 2013.