Do you have other Profile Plugins?
wpForo replace all avatars without any issue, this is something strange. please do following:
1. make sure these options are enabled in Forums > Settings > features admin page:
- Replace Author Avatar with Forum Profile Avatar
- Enable Avatars
- Enable Custom Avatars
2. Navigate to Dashboard > Forums > Dashboard admin page and click on [Delete Users Cache] button.
3. Disable other plugins and test it again.
Could you please check it with latest version of WP and wpForo. wpForo has hundreds of small features and that impossible to check on each WordPress version. Maybe wpForo Avatars don't replace other avatars in WP 4.8.4 version.
With the version of WordPress 4.9.1 also avatars do not work.
Version 4.8.4 is the penultimate version. Next 4.9.1
In the previous version of wpforo it was impossible to change the avatar. When changing the avatar - it remained cached on the client's browser side. But the avatars were displayed in Wordpress comments. Now integration is absent.


