Problem
You want to change a UCR variable and you get an error message that reads
W: path/of/the/variable is overridden by scope "ldap"
Solution
Check for UCR policies that are applied to either the LDAP base or a specific OU.

You can also check via the terminal:
udm policies/registry list
After applying/editing policies, you might have to restart:
systemctl restart univention-directory-policy.service