According to ITU-T, all low path alarms should send AIS downstream. In the NG-SDH equipments, it doesn't happen.
Nothing can be done. The insertion of AIS si disable on NG-SDH equipments because of historical problems.
All NG-SDH software is configured to not insert AIS downtream. This decision had been taken because of historical problems.
As the customer complained about this "out of standard" function, it should be intersting if this function could be configurable, like HP_TIM, HP_UNEQ and HP_PLM.
This technical case should be accepted to inform another engineers if they face the same problems.