I had the same problem writing to several worksheets in an Excel file from a scheduled SQL Agent job. It worked fine for about 4 months. Then suddenly with no changes to the package, one of the 5 worksheets was no longer populated with data. No error message generated and it worked fine on every test from Visual Studio and Data Tools (the old "BIDS" tools as we used to call it.)
I never did find a solution and it continues to not write any data to that single worksheet of the 5 in the Excel file. (So answers above about the Account that the job runs under from SQL Agent does not have the appropriate permissions is NOT a correct answer for this issue.)
Plus, a new package I built today is having the same issue, only this one has only a single worksheet. Again, works fine in the development environment, but no data appears in the destination file and no errors. Not only that, but the timestamp on the file is the same as the template file -- it seems that it never even TRIES to write to the file.
Checking each run log for the package in the Integration Services Catalog has an entry in each log that shows 9K+ records "written" for the dataflow task.
Lastly, if I change the destination file name, the SQL Agent job generates the expected error, so that rules out answers that guess that the path is wrong.
This is bizarre. And exasperating.