diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
index 4d821091a2750..4d8e677e03739 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
@@ -5330,6 +5330,9 @@ describe('ReactDOMFizzServer', () => {
       });
       expect(getVisibleChildren(container)).toEqual(['AB', 'C']);
 
+      // Hydration uses a different renderer runtime (Fiber instead of Fizz).
+      // We reset _currentRenderer here to not trigger a warning about multiple
+      // renderers concurrently using these contexts
       ContextA._currentRenderer = null;
       ServerContext._currentRenderer = null;
       ReactDOMClient.hydrateRoot(container, <App />);
diff --git a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js
index 2a3d5cefa1bca..f477bba451a6e 100644
--- a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js
+++ b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js
@@ -619,6 +619,9 @@ describe('ReactFlightDOMBrowser', () => {
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
     await act(async () => {
+      // Client uses a different renderer.
+      // We reset _currentRenderer here to not trigger a warning about multiple
+      // renderers concurrently using this context
       ContextA._currentRenderer = null;
       root.render(<Client />);
     });