Hi Pankaj,
The fact that this is becoming a non-consistent issue now, compared with when you reported this (all users) is driving me more and more thinking in the same direction of "something changed unintentionally", as my previous answer.
Because everything worked before, then all users got pop-up screen, then some users getiing back the "normal-mode (without pop-up)".
Either there were changes made on the profile-level (ask your administrator) or user-level (for example check via SUIM, look at the overview of change documents of those users getting back to normal mode), or something in the BW-portal as well (ask you administrator). Or there were some update/change functionally which could impact this behaviour, hence compare with other BW-systems.
I hope this will help you.
Regards,
Andre