update substitution logical

processor/k8sattributesprocessor/internal/kube/kube.go

@@ -187,19 +187,15 @@ func (r *FieldExtractionRule) extractFromNamespaceMetadata(metadata map[string]s
 func (r *FieldExtractionRule) extractFromMetadata(metadata map[string]string, tags map[string]string, formatter string) {
 	if r.KeyRegex != nil {
 		for k, v := range metadata {
-			var name string
-			if r.HasKeyRegexReference {
-				result := []byte{}
-				for _, submatches := range r.KeyRegex.FindAllStringSubmatchIndex(k, -1) {
-					result = r.KeyRegex.ExpandString(result, r.Name, k, submatches)
-				}
-				name = string(result)
-				tags[name] = v
-			} else {
-				if r.KeyRegex.MatchString(k) && v != "" {
+			if r.KeyRegex.MatchString(k) && v != "" {
+				var name string
+				if r.HasKeyRegexReference {
+					result := []byte{}
+					name = string(r.KeyRegex.ExpandString(result, r.Name, k, r.KeyRegex.FindStringSubmatchIndex(k)))
+				} else {
 					name = fmt.Sprintf(formatter, k)
-					tags[name] = v
 				}
+				tags[name] = v
 			}
 		}
 	} else if v, ok := metadata[r.Key]; ok {