Tried to reproduce the issue and I think managed it, at least partly. Closing the workflow in an executed state, reopen the workflow and open one of the Excel Reader leads to that “Select first sheet with data” is selected even though it was saved with “Select sheet with name”, closing (without saving) and reopen the dialog will result in the correct selection. This is definitely a problem, for which I will create a ticket, but what I did not manage to get this during execution.
Edit: Filed a ticket with internal number AP-18133