Yes, Discourse recently changed the way it handles SSO login attempts for users with unverified email addresses. If the require_activation SSO parameter is set to true, users from the SSO provider site are no longer being matched with existing Discourse users by their email address. You can find some details for dealing with this here: Debug and fixing common DiscourseConnect issues.
There are a couple of possible solutions for you. If it’s only affecting a few users on your site, you can try the approach that’s outlined in the topic I linked to above. If it’s affecting many users, you may need to add some code to your WordPress site to prevent the require_activation parameter from being set to true.
How were the users created on your WordPress and Discourse sites? Were users imported into either of them?