Question: What should a UE do when it receives an extension field with additional entries in addition to the ones carried by the original field?
Option 1: Ignore the additional entries and only use the original field.
Option 2: Create a combined list by concatenating the additional entries included in the extension field to the original field while maintaining the order among both the original and the additional entries, and apply the same behaviour as defined for the original field.
Option 3: Replace the original field with the additional entries received in the extension field.
Option 4: Discard the entire message and send an error response.
Explanation: According to the 3GPP specification, when a UE receives an extension field with additional entries, it should create a combined list by concatenating the additional entries included in the extension field to the original field while maintaining the order among both the original and the additional entries. This ensures that the UE can properly process the updated information and apply the same behaviour as defined for the original field.