Our customer have an old (2012) Android application on a Lenovo tablet that is paired with MZ320 and was working fine. When the MZ320 went EOS and they bought a few  iMZ320 without pre testing  but their app did not work.  The partner was able to replace it with old MZ320 stock since it was just a few printers. 
Last year, we did a test with the bluetooth only P4T demo unit of mine and it was printing fine using line_print mode  so they ordered.
Now the new P4T printers arrive  with same SKU as my demo unit  but it won't accept any BT printing from their Android Application.
 
The Android Zebra Utilities  Ticketing (driving) demo program works on both P4T printers without any problem.
 
Their application can still print on my demo unit   but cannot on their new unit.    Same SKU, same firmware, same setting.
I have attached the allcv of both printers  and also the captured data from the my good demo unit.
We tried to capture data from the new not good P4t but there was none.
 
Would really appreciate any help.