This is caused by the way the GL account system is configured.  When selecting specific accounts , rather than account codes, the system adds these entire accounts as selected to the pledge payments.  To have the pledge payment  distribution accounts update and reflect the designation mapping code we will have to perform the following steps:

1. Go to Administration, General Ledger Setup, [ACCOUNT], Define Transaction Mappings, Payments tab
2. Edit or Add a record solely for pledge payments and select/enter account codes rather than specific accounts
3. Save the changes.  Following pledge payments will respect segment mappings for designations and update accordingly