I sincerely hope you are asking that to try and narrow down the possible known causes of this flaw. If you are even remotely thinking about that as a possible workflow, fuggedaboutit. A workflow that required a local copy of the DST file is not even remotely acceptable.
I agree JGerth. And as I have mention earlier we have other people in the office accessing the sheet set the same way I do and they CAN open multiple sheets.