diff --git a/workspaces/arborist/lib/arborist/build-ideal-tree.js b/workspaces/arborist/lib/arborist/build-ideal-tree.js
index d04ddf27b6965..bf7268df443c3 100644
--- a/workspaces/arborist/lib/arborist/build-ideal-tree.js
+++ b/workspaces/arborist/lib/arborist/build-ideal-tree.js
@@ -1300,6 +1300,8 @@ This is a one-time fix-up, please be patient...
       }
 
       const parentEdge = node.parent.edgesOut.get(edge.name)
+      if (!parentEdge) continue
+
       const { isProjectRoot, isWorkspace } = node.parent.sourceReference
       const isMine = isProjectRoot || isWorkspace
       const conflictOK = this[_force] || !isMine && !this.#strictPeerDeps