diff --git a/petab/v1/visualize/plotting.py b/petab/v1/visualize/plotting.py
index e690df2c..86299225 100644
--- a/petab/v1/visualize/plotting.py
+++ b/petab/v1/visualize/plotting.py
@@ -63,7 +63,10 @@ def __init__(
         self.data_to_plot = data_to_plot
         self.data_to_plot.sort_index(inplace=True)
 
-        self.conditions = conditions_
+        try:
+            self.conditions = conditions_.copy()
+        except AttributeError:
+            self.conditions = conditions_
         self.inf_point = (
             np.inf in self.conditions if self.conditions is not None else False
         )