This is not reproducible in a simple hello-world PyQt app, so it seems to be something specific about our editing environment or app that is triggering this. More experimentation is required.

Working hello-world:

```diff
diff --git a/qt/aqt/__init__.py b/qt/aqt/__init__.py
index eca04b261..cb5aa863b 100644
--- a/qt/aqt/__init__.py
+++ b/qt/aqt/__init__.py
@@ -567,7 +567,39 @@ def write_profile_results() -> None:
profiler.dump_stats(profile)


+
+class MainWindow(QMainWindow):
+ def __init__(self):
+ super().__init__()
+ self.setWindowTitle("Hello, World! - PyQtWebEngine")
+ self.resize(800, 600)
+
+ # Create a QWebEngineView widget
+ self.browser = QWebEngineView()
+
+ # Set the HTML content for the browser
+ html_content = """
+
+
+
+ Hello, World!
+
+
+

Hello, World!

+
+
+
+ """
+ self.browser.setHtml(html_content)
+
+ # Set the browser as the central widget
+ self.setCentralWidget(self.browser)
+
def run() -> None:
+ app = QApplication(sys.argv)
+ window = MainWindow()
+ window.show()
+ sys.exit(app.exec())
print("Preparing to run...")
try:
_run()
```

Start by reproducing the behavior on macOS with Qt 6.8.1, then compare the app's editing environment with the working PyQt example in qt/aqt/__init__.py. The issue is complete only when the trigger is isolated and the Caps Lock dead-key behavior is fixed or clearly documented.

Written by the indexing model from the issue text.