Not able to create a unique nodes

Hello All,
when I run the query then I get the output as per the screenshot but. When I try to create new nodes with the details of these nodes. It creating two nodes with the same details. It is ignoring the node "2016" one.
Match (e:RowName)-[:ASSOCIATED_COLUMN]->(f:Column)-[:ASSOCIATED_COLUMN *1..]->(g:Column)

Query to create the nodes:

create (z:Matrix{