diff --git a/src/anemoi/datasets/create/functions/sources/xarray/coordinates.py b/src/anemoi/datasets/create/functions/sources/xarray/coordinates.py
index 8e92b0e6..f08a00f7 100644
--- a/src/anemoi/datasets/create/functions/sources/xarray/coordinates.py
+++ b/src/anemoi/datasets/create/functions/sources/xarray/coordinates.py
@@ -30,7 +30,7 @@ def extract_single_value(variable):
     if np.issubdtype(variable.values.dtype, np.datetime64):
         if len(shape) == 0:
             return to_datetime(variable.values)  # Convert to python datetime
-        assert False, (shape, variable.values)
+        assert False, (shape, variable.values[:2])
 
     if np.issubdtype(variable.values.dtype, np.timedelta64):
         if len(shape) == 0:
diff --git a/src/anemoi/datasets/create/functions/sources/xarray/metadata.py b/src/anemoi/datasets/create/functions/sources/xarray/metadata.py
index 471fc6bc..877045b8 100644
--- a/src/anemoi/datasets/create/functions/sources/xarray/metadata.py
+++ b/src/anemoi/datasets/create/functions/sources/xarray/metadata.py
@@ -100,7 +100,9 @@ def _get(self, key, **kwargs):
                 else:
                     return kwargs.get("default", None)
 
-        key = self._mapping.from_user(key)
+        if self._mapping is not None:
+            key = self._mapping.from_user(key)
+
         return super()._get(key, **kwargs)
 
 
diff --git a/src/anemoi/datasets/create/functions/sources/xarray/time.py b/src/anemoi/datasets/create/functions/sources/xarray/time.py
index eb2e2eaa..65c97165 100644
--- a/src/anemoi/datasets/create/functions/sources/xarray/time.py
+++ b/src/anemoi/datasets/create/functions/sources/xarray/time.py
@@ -91,8 +91,8 @@ def __init__(self, date_coordinate, step_coordinate):
         self.step_coordinate = step_coordinate
 
     def fill_time_metadata(self, time, metadata):
-        metadata["date"] = self.date_coordinate.single_value.strftime("%Y%m%d")
-        metadata["time"] = self.date_coordinate.single_value.strftime("%H%M")
-        hours = self.step_coordinate.total_seconds() / 3600
+        metadata["date"] = time.strftime("%Y%m%d")
+        metadata["time"] = time.strftime("%H%M")
+        hours = metadata[self.step_coordinate.name].total_seconds() / 3600
         assert int(hours) == hours
         metadata["step"] = int(hours)