No lines printed on Sales Packing Slip pro-forma

Hi All, I am facing an issue with D365 Sales Packing slip proforma i.e. no lines are printed on the report. Its happening on the Platform update 12 , application version 7.3 .  the lines data does appear if I post the packing slip and print the report. i found one of the resolutions from Microsoft support for same issue with Sales confirmation report (attached in the screen shot) however i noticed that its already been implemented this way in  SalesPackingSlipDp class,  When i debugged, the lines data does seem to be populating as expected. and the weired part is, in some of the instances, the lines data does prints on the pro-forma report but in most cases it doesn't. so far i have not been able to identify the scenario exactly when it does print and when it doesn't. However in noticed the few times it printed when literally stepped into each every method in the call stack. i also built  all the models sync db etc. issue still persist. after the build i noticed lines got printed on the proforma report the first i run after running the app but then it doesn't.  also, i redeployed the report, i have tried restarting the report server. also this was happening to the out of the box system so kinda rule out the possibility that its happening due to something that i changed. I am continuing to investigate it further, but thought to post it here as well incase anyone had faced this issue and have any resolution / workaround to suggest?