Try to reduce the joins for the sub propertys in #TYPO3Flow...

Doctrine_Query.diff

Index: flow/Packages/Framework/TYPO3.Flow/Classes/TYPO3/Flow/Persistence/Doctrine/Query.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- flow/Packages/Framework/TYPO3.Flow/Classes/TYPO3/Flow/Persistence/Doctrine/Query.php	(revision )
+++ flow/Packages/Framework/TYPO3.Flow/Classes/TYPO3/Flow/Persistence/Doctrine/Query.php	(revision )
@@ -528,10 +528,14 @@
 		$propertyPathParts = explode('.', $propertyPath);
 		$conditionPartsCount = count($propertyPathParts);
 		for ($i = 0; $i < $conditionPartsCount - 1; $i++) {
+      if (is_array($this->joins) && $previousJoinAliasKey = array_search($previousJoinAlias . '.' . $propertyPathParts[$i], $this->joins)) {
+        $previousJoinAlias = $previousJoinAliasKey;
+      } else {
-			$joinAlias = $propertyPathParts[$i] . $this->joinAliasCounter++;
-			$this->queryBuilder->leftJoin($previousJoinAlias . '.' . $propertyPathParts[$i], $joinAlias);
-			$this->joins[$joinAlias] = $previousJoinAlias . '.' . $propertyPathParts[$i];
-			$previousJoinAlias = $joinAlias;
+        $joinAlias = $propertyPathParts[$i] . $this->joinAliasCounter++;
+        $this->queryBuilder->leftJoin($previousJoinAlias . '.' . $propertyPathParts[$i], $joinAlias);
+        $this->joins[$joinAlias] = $previousJoinAlias . '.' . $propertyPathParts[$i];
+        $previousJoinAlias = $joinAlias;
+      }
 		}
 
 		return $previousJoinAlias . '.' . $propertyPathParts[$i];