Cannot change LDAP password on Synology NAS

[db4]

I have a problem with pGina 3.2.4.0/Synology DSM 6.1 (probably related to #323): pGina silently fails to change LDAP password on Synology OpenLDAP server. Network sniffer shows that pGina issues request

Lightweight Directory Access Protocol
    LDAPMessage modifyRequest(4) "uid=xxxx,cn=users,dc=ldap,dc=xxxx,dc=xxxx"
        messageID: 4
        protocolOp: modifyRequest (6)
            modifyRequest
                object: uid=xxxx,cn=users,dc=ldap,dc=xxxx,dc=xxxx
                modification: 1 item
                    modification item
                        operation: replace (2)
                        modification userPassword
                            type: userPassword
                            vals: 1 item
                                AttributeValue: {SHA}fEqNCco3Yq9h5ZUglD3CZJT4lBs=

that fails with

Lightweight Directory Access Protocol
    LDAPMessage modifyResponse(24) constraintViolation (Password fails quality checking policy)
        messageID: 24
        protocolOp: modifyResponse (7)
            modifyResponse
                resultCode: constraintViolation (19)
                matchedDN: 
                errorMessage: Password fails quality checking policy

Server responds with an error, but pGina reports that the password is successfully changed.

Why pGina send encrypted password in AttributeValue? If I change userPassword with another software (JXplorer), AttributeValue field contains non-encrypted data and everything works as expected.