After uninstalling the leave_children_open option, and restarting properly all the servers, check all the NX.env files from Secondaries (in Conventional) or from Applications (in Advanced Availability), if there is still a row such as:
If exists, replace this row with the one from NX.env from the Primary or from the Background, that should be something like:
! @NX_LEAVE_CHILDREN_OPEN= Deinstalled Fri Apr 07 15:23:32 2017
Restart the SDM Services.