invoice not paid in listing but paid in customer report

[scar]

hello i am using gnucash 2.4.10 r21973 on ubuntu 12.04.

i have some discrepancies with my invoices for some customers.

when i search for a customer and look at their invoices, there is one
that is showing not being paid, even though it has.  when i produce a
customer report it shows the balance due as $0.00.  this only happens
for a select few customers.  how to fix this discrepancy?  thanks