Question: Under which condition will the MME trigger the UE Context Release procedure upon receiving an E-RAB MODIFICATION INDICATION message?
Option 1: When all E-RABs previously included in the UE Context are present in the E-RAB MODIFICATION INDICATION message.
Option 2: When the E-RAB MODIFICATION INDICATION message contains multiple E-RAB ID Information Elements (IEs) set to the same value, or if it lacks a Cell Access Mode IE set to 'hybrid' within the CSG Membership Info IE.
Option 3: If the UE Context Release Request procedure is already in progress for the specific UE.
Option 4: When the E-RAB MODIFICATION INDICATION message includes new E-RABs not previously part of the UE Context.
Explanation: This option correctly identifies two abnormal conditions triggering the UE Context Release procedure: Duplicate E-RAB IDs (indicating inconsistency) and Missing or Incorrect Cell Access Mode for CSG Membership (signifying misconfiguration), both necessitating context release to maintain network integrity and functionality.