diff --git a/pkg/utils/overriding/merging.go b/pkg/utils/overriding/merging.go
index cf58a45d8..cb4aa63f0 100644
--- a/pkg/utils/overriding/merging.go
+++ b/pkg/utils/overriding/merging.go
@@ -36,6 +36,10 @@ func MergeDevWorkspaceTemplateSpec(
 	if err := ensureNoConflictsWithPlugins(mainContent, pluginFlattenedContents...); err != nil {
 		return nil, err
 	}
+	// also need to ensure no conflict between parent and plugins
+	if err := ensureNoConflictsWithPlugins(parentFlattenedContent, pluginFlattenedContents...); err != nil {
+		return nil, err
+	}
 
 	result := workspaces.DevWorkspaceTemplateSpecContent{}
 
diff --git a/pkg/utils/overriding/overriding.go b/pkg/utils/overriding/overriding.go
index c73b5b32c..6edcc3d13 100644
--- a/pkg/utils/overriding/overriding.go
+++ b/pkg/utils/overriding/overriding.go
@@ -116,6 +116,9 @@ func OverrideDevWorkspaceTemplateSpec(original *workspaces.DevWorkspaceTemplateS
 
 func ensureOnlyExistingElementsAreOverridden(spec *workspaces.DevWorkspaceTemplateSpecContent, overrides workspaces.Overrides) error {
 	return checkKeys(func(elementType string, keysSets []sets.String) []error {
+		if len(keysSets) <= 1 {
+			return []error{}
+		}
 		specKeys := keysSets[0]
 		overlayKeys := keysSets[1]
 		newElementsInOverlay := overlayKeys.Difference(specKeys)