Site access configuration is set as:

Incoming users are still prompted to request access, and the administrators are emailed:
Subject: Someone requested access to Jira
ABC requested access to Jira
Name (email) requested access to Jira on ---.atlassian.net. Name currently consumes a seat in your license and has access to some of your products. You can approve access requests from your Site administration.
Why would this be the case?