diff --git a/src/lib/Repository/NameSchema/SchemaIdentifierExtractor.php b/src/lib/Repository/NameSchema/SchemaIdentifierExtractor.php
index 803c6c814d..cb7d76c51f 100644
--- a/src/lib/Repository/NameSchema/SchemaIdentifierExtractor.php
+++ b/src/lib/Repository/NameSchema/SchemaIdentifierExtractor.php
@@ -27,7 +27,7 @@ final class SchemaIdentifierExtractor implements SchemaIdentifierExtractorInterf
      */
     public function extract(string $schemaString): array
     {
-        $allTokens = '/<([^>]+)>/';
+        $allTokens = '/<([^>-]+)>/';
 
         if (false === preg_match_all($allTokens, $schemaString, $matches)) {
             return [];
@@ -36,7 +36,6 @@ public function extract(string $schemaString): array
         $strategyIdentifiers = [];
         foreach ($matches[1] as $tokenExpression) {
             $tokens = explode('|', $tokenExpression);
-
             foreach ($tokens as $token) {
                 $strategyToken = explode(':', $token, 2);
 
@@ -47,8 +46,11 @@ public function extract(string $schemaString): array
                     $strategy = 'field';
                 }
 
+                $token = preg_replace('/[()<>\[\]]/', '', $token);
                 $strategyIdentifiers[$strategy][] = $token;
             }
+
+            $strategyIdentifiers[$strategy] = array_unique($strategyIdentifiers[$strategy]);
         }
 
         return $strategyIdentifiers;
diff --git a/tests/lib/Repository/NameSchema/SchemaIdentifierExtractorTest.php b/tests/lib/Repository/NameSchema/SchemaIdentifierExtractorTest.php
index 76a4d2dc97..bf60625f60 100644
--- a/tests/lib/Repository/NameSchema/SchemaIdentifierExtractorTest.php
+++ b/tests/lib/Repository/NameSchema/SchemaIdentifierExtractorTest.php
@@ -67,6 +67,15 @@ public function getDataForTestExtract(): iterable
                 'field' => ['bar', 'baz'],
             ],
         ];
+
+        $schemaString = '<specification|(<name> <image1>)-<custom:bar|baz>-<field:bar|baz>';
+        yield $schemaString => [
+            $schemaString,
+            [
+                'field' => ['specification', 'name', 'image1', 'baz', 'bar'],
+                'custom' => ['bar'],
+            ],
+        ];
     }
 
     protected function setUp(): void