Upon updating Sharepoint Online site properties(eg., title, description) through REST API, the updated values don't reflect until site information page is manually accessed.
Update site properties is working fine for SPOnpremise but not for SPOnline
Steps:
1. Update site properties (title/description) through REST API
2. Get the site properties via REST/UI. It can be now observed that properties are not updated
3. Access site via browser and click on site settings - site information
4. The new properties are displayed here.
5. Now repeat step 2, and the updated values are reflected now.
While working with REST, it is not expected that user would access SPO via browser to get these properties reflect rightly.
Please refer screenshots





