diff --git a/notebooks/AGIPD/AGIPD_Correct_and_Verify.ipynb b/notebooks/AGIPD/AGIPD_Correct_and_Verify.ipynb
index 86a529138f328b3aa206c342b9511f1cea950ddf..943454e7137feab4142d6afccae08cd332c9dc8c 100644
--- a/notebooks/AGIPD/AGIPD_Correct_and_Verify.ipynb
+++ b/notebooks/AGIPD/AGIPD_Correct_and_Verify.ipynb
@@ -626,8 +626,8 @@
     "            else:\n",
     "                module_timestamps[key] = \"NA\"\n",
     "        timestamps[qm] = module_timestamps\n",
-    "        \n",
-    "if not karabo_da:  # Dark constants are missing for all modules.\n",
+    "\n",
+    "if not karabo_da:  # Raise Error if dark constants are missing for all modules.\n",
     "    raise ValueError(\"Dark constants are missing for all modules.\")\n",
     "\n",
     "seq = sequences[0] if sequences else 0\n",
diff --git a/src/cal_tools/agipdlib.py b/src/cal_tools/agipdlib.py
index 576b07559e3281684ff51328b81c12c3ea4fd2a5..62061f47f4236012e2da2c5e53a5198baa814fed 100644
--- a/src/cal_tools/agipdlib.py
+++ b/src/cal_tools/agipdlib.py
@@ -1398,7 +1398,7 @@ class AgipdCorrections:
             when[cname] = mdata["creation-time"]
             if when[cname]:
                 with h5py.File(mdata["path"], "r") as cf:
-                    cons_data[cname] = cf[f"{base_key}/data"][()]
+                    cons_data[cname] = np.copy(cf[f"{base_key}/data"])
                     # Set variant to 0 if the attribute is missing
                     # as for old constants.
                     if "variant" in cf[base_key].attrs.keys():
@@ -1406,6 +1406,7 @@ class AgipdCorrections:
                     else:
                         variant[cname] = 0
 
+        # skip initializing the constants if a dark constant is missing.
         if self.validate_constants_availability(cons_data, karabo_da):
             self.init_constants(cons_data, when, module_idx, variant)
             return when
@@ -1504,6 +1505,7 @@ class AgipdCorrections:
                     cons_data[cname] = np.copy(cf[f"{dataset}/data"])
                     variant[cname] = cf[dataset].attrs["variant"] if cf[dataset].attrs.keys() else 0  # noqa
 
+        # skip initializing the constants if a dark constant is missing.
         if self.validate_constants_availability(cons_data, karabo_da):
             self.init_constants(cons_data, when, module_idx, variant)
             return when