diff --git a/source/MulensModel/fitdata.py b/source/MulensModel/fitdata.py
index be05f824..64a780cf 100644
--- a/source/MulensModel/fitdata.py
+++ b/source/MulensModel/fitdata.py
@@ -301,7 +301,7 @@ def fit_fluxes(self):
                 if not proceed:
                     self._calculate_magnifications(bad=False)
                     self._blend_flux = self.fix_blend_flux
-                    self._source_fluxes = self.fix_source_flux
+                    self._source_fluxes = np.array(self.fix_source_flux)
                     return
 
         (xT, y) = self._setup_linalg_arrays()
@@ -324,20 +324,21 @@ def fit_fluxes(self):
         # Record the results
         if self.fix_source_flux_ratio is False:
             if self.fix_source_flux is False:
-                self._source_fluxes = results[0:self._model.n_sources]
+                source_fluxes = results[0:self._model.n_sources]
             else:
-                self._source_fluxes = []
+                source_fluxes = []
                 index = 0
                 for i in range(self._model.n_sources):
                     if self.fix_source_flux[i] is False:
-                        self._source_fluxes.append(results[index])
+                        source_fluxes.append(results[index])
                         index += 1
                     else:
-                        self._source_fluxes.append(self.fix_source_flux[i])
+                        source_fluxes.append(self.fix_source_flux[i])
 
         else:
-            self._source_fluxes = [results[0],
-                                   results[0] * self.fix_source_flux_ratio]
+            source_fluxes = [results[0], results[0]*self.fix_source_flux_ratio]
+
+        self._source_fluxes = np.array(source_fluxes)
 
         if self.fix_blend_flux is False:
             self._blend_flux = results[-1]
diff --git a/source/MulensModel/tests/test_FitData.py b/source/MulensModel/tests/test_FitData.py
index ede364d4..196e7211 100644
--- a/source/MulensModel/tests/test_FitData.py
+++ b/source/MulensModel/tests/test_FitData.py
@@ -179,6 +179,7 @@ def _run_true_value_test(
         almost(my_fit.blend_flux, self.f_b)
         almost(my_fit.source_fluxes[0], self.f_s_1)
         almost(my_fit.source_fluxes[1], self.f_s_2)
+        assert isinstance(my_fit.source_fluxes, (np.ndarray))
 
         peak_index = 500
         mod_fluxes = my_fit.get_model_fluxes()
@@ -226,6 +227,7 @@ def _run_q_flux_test_arbitrary(
         almost(
             my_fit.source_fluxes[1]/my_fit.source_fluxes[0],
             fix_q_flux)
+        assert isinstance(my_fit.source_fluxes, (np.ndarray))
 
     def test_value_error(self):
         with self.assertRaises(ValueError):
diff --git a/source/MulensModel/version.py b/source/MulensModel/version.py
index 2a9dde58..e615ea2b 100644
--- a/source/MulensModel/version.py
+++ b/source/MulensModel/version.py
@@ -1 +1 @@
-__version__ = "2.21.0"
+__version__ = "2.21.1"