diff --git a/lib/ldclient-rb/evaluation_detail.rb b/lib/ldclient-rb/evaluation_detail.rb
index 5d57aaff..55d9df87 100644
--- a/lib/ldclient-rb/evaluation_detail.rb
+++ b/lib/ldclient-rb/evaluation_detail.rb
@@ -288,7 +288,7 @@ def as_json(*) # parameter is unused, but may be passed if we're using the json
     # Same as {#as_json}, but converts the JSON structure into a string.
     # @return [String]
     def to_json(*a)
-      as_json.to_json(a)
+      as_json.to_json(*a)
     end
 
     # Allows this object to be treated as a hash corresponding to its JSON representation. For
diff --git a/lib/ldclient-rb/flags_state.rb b/lib/ldclient-rb/flags_state.rb
index 57807859..05b66380 100644
--- a/lib/ldclient-rb/flags_state.rb
+++ b/lib/ldclient-rb/flags_state.rb
@@ -81,7 +81,7 @@ def as_json(*) # parameter is unused, but may be passed if we're using the json
 
     # Same as as_json, but converts the JSON structure into a string.
     def to_json(*a)
-      as_json.to_json(a)
+      as_json.to_json(*a)
     end
   end
 end
diff --git a/lib/ldclient-rb/impl/model/feature_flag.rb b/lib/ldclient-rb/impl/model/feature_flag.rb
index 6c93877b..34dd1bed 100644
--- a/lib/ldclient-rb/impl/model/feature_flag.rb
+++ b/lib/ldclient-rb/impl/model/feature_flag.rb
@@ -103,7 +103,7 @@ def as_json(*) # parameter is unused, but may be passed if we're using the json
 
         # Same as as_json, but converts the JSON structure into a string.
         def to_json(*a)
-          as_json.to_json(a)
+          as_json.to_json(*a)
         end
       end
 
diff --git a/lib/ldclient-rb/impl/model/segment.rb b/lib/ldclient-rb/impl/model/segment.rb
index 6b8f3cb6..83c1dc90 100644
--- a/lib/ldclient-rb/impl/model/segment.rb
+++ b/lib/ldclient-rb/impl/model/segment.rb
@@ -84,7 +84,7 @@ def as_json(*) # parameter is unused, but may be passed if we're using the json
 
         # Same as as_json, but converts the JSON structure into a string.
         def to_json(*a)
-          as_json.to_json(a)
+          as_json.to_json(*a)
         end
       end