diff --git a/pymatgen/electronic_structure/bandstructure.py b/pymatgen/electronic_structure/bandstructure.py
index <HASH>..<HASH> 100644
--- a/pymatgen/electronic_structure/bandstructure.py
+++ b/pymatgen/electronic_structure/bandstructure.py
@@ -879,7 +879,7 @@ class BandStructureSymmLine(BandStructure, MSONable):
                 'fcoords']
         if len(self.projections) != 0:
             d['structure'] = self.structure.as_dict()
-            d['projections'] = {str(int(spin)): v.tolist()
+            d['projections'] = {str(int(spin)): np.array(v).tolist()
                                 for spin, v in self.projections.items()}
         return d
fix bug in BS -> make variable numpy array instead of list, for fixing as_dict method