In my case I found that the Q-Feeds Connect add-on was causing this. With the option in Q-Feeds 'Register domain feeds' enabled, it puts a blacklist file at /usr/local/etc/unbound/qfeeds-blocklists.conf . Even with Unbound blacklists turned off, this file remains & keeps blocking. Unbound whitelists don't affect it, & there appears to be no way to whitelist in Q-Feeds.
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