Hi @karpuram sai di 

It can be caused by a reference to a discovery_status record that does not exist or has been deleted

 Check your script include if somewhere it is looking for the reference which is invalid (empty) and it can't find a record to display.

As per this blog, This is a known issue . In that case raise a case to your ServiceNow vendor and look for ETA for the fix.

https://www.findbugzero.com/operational-defect-database/vendors/sn/defects/PRB1919668