Fix bug whereby adding unitful NDCube and NDData did not output result with underlying arrays as dask.

Author: DanRyanIrish

changelog/880.bugfix.rst

@@ -0,0 +1 @@
+Adding unitful `~ndcube.NDCube` and ``astropy.nddata.NDData`` objects backed by ``dask`` did not preserve underlying arrays as ``dask`` arrays. This is now fixed.

ndcube/ndcube.py

@@ -983,7 +983,7 @@ def _arithmetic_operate_with_nddata(self, operation, value):
         if operation == "add":
             # Handle units
             if self.unit is not None and value.unit is not None:
-                value_data = (value.data * value.unit).to_value(self.unit)
+                value_data = value.data * (value.unit / self.unit).to(u.dimensionless_unscaled)
             elif self.unit is None and value.unit is None:
                 value_data = value.data
             else: