F5 GTM resolution issue

Can you share how the zones are configured and how you have setup the WIPs and zone records.Are you delegating the TLD or is it just subzone. 

can you draw the query architecure you have , so technically your TLD should hosted on your DNS externally as the registrar will send traffic on external provider and then the subzone should be aliased to the GTM. Once the subzone is deligated the WIP should be configured under the subzone on your GTM. Can you confirm that you are aligned with same design.
Did you queried the same subzone record that is present in your GTM. For example if your URL is xyz.abc.com it might be aliased to xyz.abc.com.gtm.abc.com ---> as you have ns records 

I do not see the packetcapture query response but i believe you have tried to create a zone replica of the external DNS which might not be sending the query correctly.