Unable to align the Department OBS to match the Resource OBS , the system does not save the changes for some reason and resets it to the incorrect Department OBS.
16.1.0
The resource was financially active with the Financial properties set incorrectly. The Financial property of the resource i.e. Financial Department and Financial location was corrected to the correct OBS and from then the Department OBS could be updated.
Resource > Financial properties.
For more information on Financially enabling resources in clarity visit the tech document reference here