Unable to Change GL Accounts in Remittance Bank of a Receipt Method

Summary

I am trying to correct the GL account in the remittance bank of a receipt method, but the GL account fields are all grayed out for this specific method/bank combination but allowed me to change others

Content

The GL Account coding is missing the correct values in segment 4 (Activity Code), for a few of the remittance banks in a few of the receipt methods.  I was able to update the GL Account detail in the Remittance Bank on some of the Receipt Methods that use the same bank account, but in one of the Receipt Methods, the GL Account fields are all grayed out.  The fields I was able to change are the same remittance bank account, so I am not sure why I was able to change it in some but not in one of them.