I am not even sure what information you need to help with this. 
We have a simple Crystal XI report with 2 group headers defined. And just by chance the creator placed the same field in both the header and footer of group 2.  The field reports different data depending on the location.  In the group2 header it reports the name of an Iowa county Linn and in the group2 footer it reports the name of a Michigan county Missaukee.
Group 1 is tax state
Group 2 is the tax county
What do we look for????

select
shipto_master.*, ISNULL((select top 1 cz.county_name from city_zip cz where cz.state = shipto_master.ship_state and cz.county_code = shipto_master.tax_county), '') as 'tax_county_name',
(select sum(quantity * taxable_amt) from shipto_detail where shipto_detail.order_id = shipto_master.order_id and shipto_detail.shipto_num = shipto_master.shipto_num and shipto_detail.status in ('S','R'))
from shipto_master
where close_flag = 'Y'
and tax_amt <> 0

Ok, that makes sense except Group 1 defines the state and group 2 the county within the state so there is only 1 data set for each county number within the state.    The footer is reporting a county from another state.
What is even more puzzeling is we modified an existing report by supressing sections and moving fields around.  We did not add any fields or calculations.  The original report works correctly.
thank you

We only had the groups like you have in the green.
We will never know.  We just started from the original report and modified it again and it works correctly.
Thank you for your help.