Hi Lokesh,
then i don't think there is any problem in your smartforms, just see all the 4 users , can you please
tell me that all the 6 users have the same SAP gui setup, see if any of the user has got correct
smartform, (no template issue), then i don't thing its smartform problem, please talk to your basis guys and ask him for patch level problem or gui problem.
Just setup the latest gui version available in those 4 user's system.
Because its not problem of smartform, its problem of display, which can be corrected either by
installing latest gui, or by patch level.