diff --git a/python/plugins/processing/algs/qgis/TilesXYZ.py b/python/plugins/processing/algs/qgis/TilesXYZ.py
index 023570d629d..5bb588e4f2d 100644
--- a/python/plugins/processing/algs/qgis/TilesXYZ.py
+++ b/python/plugins/processing/algs/qgis/TilesXYZ.py
@@ -307,6 +307,7 @@ class MBTilesWriter:
         conn.close()
 
     def _init_zoom_layer(self, zoom):
+        self._zoom_ds = None
         west_edge, south_edge, east_edge, north_edge = self.extent
         first_tile = Tile(*deg2num(north_edge, west_edge, zoom), zoom)
         last_tile = Tile(*deg2num(south_edge, east_edge, zoom), zoom)
@@ -409,7 +410,7 @@ LEAFLET_TEMPLATE = '''
        right: 10px;
        top: 10px;
        bottom: 10px;
-       width: 600px; 
+       width: 600px;
        height: 400px;
     }}
   </style>