[Tricia S.]

I have a solution that might work.

What I do is rather than use the the prefill _vlookupParentID, I use a combination of Rules and Cascading drop downs.

This looks to the deepest level I have:
Here is the lookup list Field:
ProjectNumber/Title,PoPMap2,Title,SLINNumber,OData__vLookupProjectID,OData__vLookupParentID,OData__vLookupID,Status,ProjectNumber/ProcasProjectNumber
and Here are the current list fields:
Project,RelatedPoP,RelatedCLIN,RelatedSLIN,_vLookupProjectID,_vLookupPoPID,_vLookupParentID,CLINStatus,ProjectNumber

Each level is going to change a bit:
Deepest level:
_vLookupProjectID= Project
_vLookupPoPID= POP
_vLookupParentID=Clin
_vLookupID= Self

Vs if I go to the CLIN setting Level
_vLookupProjectID= Project
_vLookupParentID= POP
_vLookupID= Self

Autofill subsequent dropdowns when they contain only one valid option needs to be selected.
On my project list I can see all related Grandchildren and great grandchildren as different vLookup lists.

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