diff --git a/src/Serilog/Settings/KeyValuePairs/KeyValuePairSettings.cs b/src/Serilog/Settings/KeyValuePairs/KeyValuePairSettings.cs
index b9ec1f059..69c619efd 100644
--- a/src/Serilog/Settings/KeyValuePairs/KeyValuePairSettings.cs
+++ b/src/Serilog/Settings/KeyValuePairs/KeyValuePairSettings.cs
@@ -148,7 +148,7 @@ where matchCallables.IsMatch(wt.Key)
 
             if (callableDirectives.Any())
             {
-                var configurationAssemblies = LoadConfigurationAssemblies(directives);
+                var configurationAssemblies = LoadConfigurationAssemblies(directives).ToList();
 
                 foreach (var receiverGroup in callableDirectives.GroupBy(d => d.ReceiverType))
                 {