Pagination shows different records when going forward and backward.

I am using server-side processing.

After the datatable rows fill out it shows 12 records and at the bottom left you see Showing 1-12 of 80.

This looks great and I can see in the email column all of the emails. (TestEmail9999@test.com through TestEmail9988@test.com)

Then I page forward once.

It shows the next 12 records and you see Showing 13 - 24 of 80.

This is correct and I can see in the email column all of the emails. (TestEmail9987@test.com through TestEmail9976@test.com)

Then I page forward once more.

It shows the next 12 records and you see Showing 25-36 of 80 in the lower left.

This also is correct and I can see in the email column all of the emails. (TestEmail9975@test.com through TestEmail9964@test.com)

Then I page BACK once.

I see the Showing change to 13 - 24 of 80 but the rows remain exactly the same. (TestEmail9975@test.com through TestEmail9964@test.com)

Then I page BACK once again. (This should be the first page)

I see the Showing change to 1 - 12 of 80 but the rows then show page 2 emails. (TestEmail9987@test.com through TestEmail9976@test.com)

Do I need to configure something for pagination to get it to work right?

thanks in advance.

H