How do I fix incorrect Balance amounts?

On my AMEX credit card registry, the balance is not being recorded as credit card registries. on all other registries, any balance owed shows up in "red", under the balance column. However, with my AMEX account, the balance shows up in italics & black, and if I change the date filters it changes the ending balance, reflecting a balance in my favor when it should be zero. I have cleared all filters and that does not resolve the issue.