Yes, misleading.
First, consumer credit reports are not designed to enable a bank to verify contingent liabilities.
Second, the guarantor is a back-up, not the primary source of repayment. Accordingly, the guarantor (who often does not have direct access to the company checkbook) is not expected to ensure each and every guaranteed loan pays within the 30 day credit bureau reporting date.
As such, including loans that may run 30 - 60 days in the Credit Score of the Guarantor undermines the reliability of the credit report and the score as indicators of how the guarantor pays his/her direct obligations.
As an aside, any bank reporting guarantors monthly (as opposed to only if they default on their guarantee) better ensure they have given the Credit Report reporting disclosure to each and every guarantor before any loans go 30 days past due.