This is likely as a result of deleting a transaction in the security section without deleting the associated certificate.
To resolve this issue, navigate to the certificates tab and fetch out the affected certificate. On the far right, click on the three dots on the select delete. Once that step is completed, the data integrity checker would disappear. The good news is that with the new “cascade delete”, once a transaction is selected to be deleted, all linked certificates and transactions are deleted at once.