[SalesForce] Getting error while adding a trusted site

I am adding some markup in "Head Markup" section of Community Builder(Settings –> Advanced) that references resources from 3rd party websites. Thus, SFDC gives me CSP violation warning in the markup. To resolve this I went to Settings –> Security –> Content Security Policy (CSP) and changed policy to:

Allow Inline Scripts and Script Access to White listed Third-party Hosts

And went on to add these sites in trusted sites. Then I whitelisted them inCSP Errors section.

However, there is this one site that is giving me error as shown below:

This site is coming in "CSP Error" section:

But when I click on whitelist button, nothing happens, the page refreshes and I get errors as:

I have also added these sites in Trusted sites in Salesforce org –> Settings –> Security Controls –> CSP Trusted Sites. But it is not working.

Any help appreciated.