The constituent record has been switched to a Custom View (designed at Config > Custom Views). When this happens, the screen will look different and not have the regular tabs and fields of a constituent record. To change it back to the regular view, called Edit Mode, ask each affected users to follow these steps:
  1. Open any constituent record
  2. Click View in the top menu
  3. Select Custom view
  4. Select <Edit Mode> and this will return the record to the customary view