Hello @AmitKulkarni,
Welcome to the Docentric community!
How are you printing the report, can you confirm that you are printing through Print Management?
If this happens only in some cases, it’s worth checking if the behavior may be due to overrides. Please take a look at our article Check if D365FO Print Management Settings Overrides are Configured for a guide.
Have you done any customizations on the report that could be causing the missing lines?
Also, I would suggest checking the technical name of the report (instructions can be found on this forum post) to make sure that the configured report is in fact the report that is being run.
I hope these troubleshooting ideas will get you closer to figuring out the root cause.
Let me know if you have additional questions.