Hi Alex,
we tried to analyze the issue to find out the root cause and we came to know that the CAML query in new form is not passing the _vLookup ID.
Please find the below query in new form
<View Scope='RecursiveAll'><Query><Where><Eq><FieldRef Name='_vLookupParentID' /><Value Type='Text'>~_vLookupID~</Value></Eq></Where><OrderBy><FieldRef Name='ID' /></OrderBy></Query></View>
we tried to get the _vLookupID in the parent list in new form using Getfieldvalue.It is returning the correct ID
In edit form
<View Scope=’RecursiveAll’><Query><Where><Eq><FieldRef Name=’_vLookupParentID’ /><Value Type=’Text’>8:1470121931290</Value></Eq></Where><OrderBy><FieldRef Name=’ID’ /></OrderBy></Query></View>
Thanks,
Navya