You mean inactive users:
- You can’t mention them because they aren’t active.
- You can’t search for them because they aren’t active.
This may be a bug but I don’t think it is:
- Inactive users are still users in the user table.
- There is a site setting to allow viewing inactive accounts - off by default but it may be enabled here:
show inactive accounts
I wonder if meta.discourse.org shows inactive customer accounts because of hosting customers? - There is a setting to delete inactive users if they needed to be removed - the default is two years:
clean up inactive users after days.