I have an issue that has popped up where when you try to select a user via either an @ mention or when you try to select a user via a user field (like the reporter field) that the full list of users does not load and ultimately you are unable to select the user you are looking for
However, if you go to user management you are able to find the missing user. This issue is happening across a large number of users in the system and impacts every user (Admin and Non Admin). This issue happened after doing an update from Jira Service Desk 7.3.7 to version 7.4.2.
I checked the global permissions for browse user however it is currently set to allow anyone to browse users so I am not sure what else might be the issue