I have seen weird things happen when people do this....

In the run section of the scheduler they put this: c:\<whereever MicroSoft put office>\EXCEL.exe "C:\<whereever you put your file>\YourFileName.xlsm"

instead of:
"C:\<whereever you put your file\YourFileName.xlsm"

so for me, I just have this in the run box.

"O:\Inventory Analyst\0-Special_Projects\Automation\634-ActiveDemandSummary.xlsm"

just a thought