Related Action Confirmation Page Leads to the Summary Tab but Returning Error (APNX-1-4205-006)

We Have a big form where there are mile stones present with save.submit and cancel buttons where if a user can save and exit.

which will create a record in the database and is accessible in the record type list.

later when the user logs in and Selects the record type and there is a related action which has continue registration he selects the related action and completes the form and the user is navigated to a confirmation page which has a button done once the user clicks the button 

we are getting the below error

and when we checked the std out log this was the message

2019-06-12 13:50:47,884 [ajp-nio-8009-exec-2133] ERROR com.appiancorp.rest.record.data.RecordRestService - Unable to retrieve record summary for record w/ type RecordType [id=51, uuid=----------------------------------, name=APPS CASE, sourceTypeStr={http://www.appian.com/ae/types/2009}DataStoreEntity, sourceUuidStr=5b8b529e-daf5-405f-8800-a81f75ea71e6@_a-0000e1d3-cf40-8000-9ba2-011c48011c48_1276917] and id CL1097CS
java.lang.NullPointerException

Thanks,

Rohan N