Shouldn't the old access token be invalidated by a refresh call?

Question

When I refresh an OAuth access token A, I get an new access token B. But A is still valid, I can still use it.

Shouldn't the old access token be invalidated by the refresh operation? If not, if it's "by design", could someone give me details about why?

Note: using Symfony with the FOSOAuthServerBundle bundle.

Answer 1

The RFC6749 section 1.5 indicates that:

Refresh tokens are issued to the client by the authorization server and are used to obtain [...] additional access tokens with identical or narrower scope

As far as I understand, the access token A may be still valid when an access token B is issued with the refreh token.