How do you test file uploads reliably in Playwright across different OS environments?

File uploads work fine locally (macOS) but fail intermittently in our Linux CI containers. We're using `page.setInputFiles()` for a standard `<input type="file">` element. The failure is inconsistent — sometimes the file is attached but the upload request never fires, other times the input appears empty when we assert on it. Is there a race condition between `setInputFiles` and the change event handler? Or is this a known Linux/headless issue with Playwright? Running Playwright 1.44 with Chromium.