The user preference is saved if any users have preselected a breakdown on a dashboard. If this breakdown was later deleted, the preferences do not get updated and so could cause the issues you are seeing now.
Login to affected instance.
1. As an admin user go to sys_user_preference_list.do
2. Filter for name = com.snc.pa.ui.preferences_dashboards and User = affected user’s name
3. select the record and delete.
4. User should Log out and log in again after deleting the preferences.
Another workaround to avoid this issue is to click inside the dashboard and scroll it to load it completely first and then scroll up, all the widgets would load as expected.