Data showing incorrectly in report

I am having trouble with a report giving back incorrect data.

The database was created in Access 2003 (*.mdb). I am using Access 2007 –
report was created in Access 2007.

The report is looking at surveys that occurred at the same place and time
(comparing differences among observers). There are two sites where a set of
surveys occurred on two different days. Only one site shows up properly in
the report with the different dates the surveys occurred. The other site has
the two survey sets under one date.

At Ole Creek a set of surveys was done on 7/10/2008 and 10/9/2008; both
dates show up in the report with corresponding surveys. Triple Divide
surveys were done on 8/5/2008 and 9/24/2008; both are listed on the report as
occurring on 9/24/2008. The control source query shows both dates for Triple
Divide.

The report layout is:
Site Header: Currently minimized – Site Name use to be here but moved so
that site name shows up at each different date a survey occurred.

Date Header: Text boxes for - Site Name and Survey Date. (The location of
Site Name between the different headers seemed to have to no effect on how
Triple Divide is shown).

Survey Header: Sub-report listing the Observers and Labels for data fields.

Detail: not visible – has the Text boxes.

Survey Footer: Text boxes that sums detail’s data fields.

Site Footer: not visible – text boxes that sums data for each site.

Group, Sort, and Total:
Group - Name
Group - Date
Group - Survey

Does anyone know why the report is doing this? Am I missing something in
the formatting or some other setting?

Thank you in advance,
Tim