User Directories - "Test Settings" replaces a new password with the old one

Within the User Directories we have one of the type "Microsoft Active Directory".
The password for the "User to log in to LDAP" has changed, so I logged in as "Internal Directory" admin to change it.

How it happens:
1) Edit the User Directory settings
2) Write the new password
3) Hit "Test Settings"
4) Hit "Save and Test"

Unfortunately the password used by ldap is still the old one and users are unable to login.

Workaround:
1) Edit the User Directory settings
2) Write the new password
3) Hit "Test Settings"
4) Write the new password (again)
5) Hit "Save and Test"