Hi everyone,
We are aware of ongoing issues with labels recently created through the AdWords API or AdWords Scripts, including:
New labels may not be visible in the AdWords UI or retrievable through the AdWords API or AdWords Scripts.
Users cannot create new labels with names matching the labels that are not visible.
Users cannot tag various entities with the labels that are not visible.
As a temporary workaround for this issue, we recommend you either use an existing label that is visible through the AdWords UI or create a new label that has a different name than the one that is not visible through the UI. We are working on addressing all of the above issues.
If you have more questions about this issue, feel free to post them on the forum.
Regards,
Mike, AdWords API Team