backport #3739

hooks/src/index.js

@@ -216,7 +216,7 @@ export function useReducer(reducer, initialState, init) {
 					}
 				});
 
-				return shouldUpdate
+				return shouldUpdate || hookState._internal.props !== p
 					? prevScu
 						? prevScu.call(this, p, s, c)
 						: true

hooks/test/browser/useState.test.js

@@ -346,4 +346,29 @@ describe('useState', () => {
 
 		expect(renderSpy).to.be.calledTwice;
 	});
+
+	// see preactjs/preact#3731
+	it('respects updates initiated from the parent', () => {
+		let setChild, setParent;
+		const Child = props => {
+			const [, setState] = useState(false);
+			setChild = setState;
+			return <p>{props.text}</p>;
+		};
+
+		const Parent = () => {
+			const [state, setState] = useState('hello world');
+			setParent = setState;
+			return <Child text={state} />;
+		};
+
+		render(<Parent />, scratch);
+		expect(scratch.innerHTML).to.equal('<p>hello world</p>');
+
+		setParent('hello world!!!');
+		setChild(true);
+		setChild(false);
+		rerender();
+		expect(scratch.innerHTML).to.equal('<p>hello world!!!</p>');
+	});
 });