phenomlab nitaaikumar I have identified an incompatibility with fof/user-directory and I suppose that's an extension you have on both of your forums.
The new version fixes that issue and also makes it more likely to work with other future extensions. There are new "no results" messages, and a special "[extension conflict]" message that can appear instead of an empty user list. Hopefully no one should ever see the latest.
You can update with
composer update clarkwinkelmann/flarum-ext-author-change
Note to translators: new translations were added and one has changed name.