One user can edit buttons in UI but other can't

Hi

I have come across some strange thing. I have 2 separate users having one common role. The issue is one user can't edit some buttons in WEB UI screen as they have been restricted through auth object CRM_SEGTYP in PFCG Role which is our requirement but other user can edit even if object is restricted.  ST01 trace is showing check successful with CRM_SEGTYP with Activity 02 but user dont have that activity in his profile.

Please let me know what could be the cause.

Thanks

Puneet