Thank you for replying with the configurations of these units. It appears you are providing 640 Kbps for the voice traffic. Does the voice traffic need additional bandwidth?
Also, I recommend you upgrade the firmware on both of these ADTRAN units to version R10.5.3.E. After doing so, please reply with the output from the show interfaces and show qos map interface ethernet 0/1 commands, and I will be happy to review it for you to see if there are any errors or drops on the interfaces.
I went ahead and flagged the "Correct Answer" on this post to make it more visible and help other members of the community find solutions more easily. If you don't feel like the answer I marked was correct, feel free to come back to this post and unmark it and select another in its place with the applicable buttons. If you still need assistance, we would be more than happy to continue working with you on this - just let us know in a reply.