Blocking ocsp.sca1b.amazontrust.com breaks Firefox OCSP query

[andersix]

With ocsp.sca1b.amazontrust.com blocked, many sites in Firefox (100 as of this post) fail with:

Secure Connection Failed

An error occurred during a connection to dummy.example.com. The OCSP server experienced an internal error.

Error code: SEC_ERROR_OCSP_SERVER_ERROR

    The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
    Please contact the website owners to inform them of this problem.

Removing/whitelisting this ocsp server address resolves the issue.