I've spend two days trying to solve it and it looks i'm stuck.
I have user and two projects with same permission scheme.
User is a member of these projects and hi has same roles.
All users are in one tempo team and team is linked with all projects.
User has priveleges "Browse project" and "View all worklogs" in both projects (tested with Permission helper).
User can see all worklogs for one project (Project 1) and only his own worklogs in other (Project 2).
By the way - in both projects user can see all worklogs in Issue->Tempo (on the right).
But he can't see other people worklogs in Issue->Worklogs (bottom of the page) in Project 2.