This test verifies below scenario:
Upon receiving SMS Message from network, UE should indicate the request to the user. When the user acknowledges the message, UE should send an SMS User Acknowledgement Message in response to the SMS Message.
So here script is looking for a SMS message with SMS_MSG_TYPE = 0 (SMS Point to Point) and Message_Type = 5 (User Acknowledgment). But some UE doesn't support sending this “SMS User Acknowledgement”, thus this issue is always a UE issue.
1) We can always see "SMS Acknowledge" message (SMS_MSG_TYPE = 2) during SMS test:
SMS Acknowledge message is just a reply to tell SMS sender that receiver has already got the SMS. And "SMS User Acknowledgement" message is different than "SMS Acknowledge".
2) Most UE supports sending "SMS Acknowledge", but not all the UE supports sending “SMS User Acknowledgement”.