We have the same Jabber version to all end users and the same configuration in the CUCM for all the users.
How can it be that the Jabbers show different information when searching for the same contacts?
Yes, there's a cache, I mentioned that before. It's 24 hours + a random period between 0 and 6 hours.
It worked because when you login with other user credentials, the cache is wiped out.
You need to delete the cache manually under the user, in their appdata folder, it will be under local