diff --git a/src/mapper/__init__.py b/src/mapper/__init__.py
index 28542fd25df4eb2d138e6c24cc8f2e7ee810693a..f2994bb4264a2d23539e9e8dc67921d149d3fd3b 100644
--- a/src/mapper/__init__.py
+++ b/src/mapper/__init__.py
@@ -125,7 +125,7 @@ class CombineMapper(RecursiveMapper):
     map_vector = map_sum
 
     def map_numpy_array(self, expr):
-        return self.combine(expr.flat)
+        return self.combine(self.rec(el) for el in expr.flat)