Can't read from Clipboard when using Firefox (Playwright/Browserstack)

Question

I am trying to use const clipboardText = await page.evaluate("navigator.clipboard.readText()"); to read content from clipboard when using Firefox with Playwright and Browserstack, and consistently getting the error: page.evaluate: navigator.clipboard.readText is not a function @debugger eval code line 208 > eval:1:21 evaluate@debugger eval code:208:30 @debugger eval code:1:44

This is how I launch the browser and connect to Browserstack:

test.beforeEach(async ({ playwright }, testInfo) => {
  
  test.setTimeout(2400000);
    patchCaps(testInfo.project.name, `${testInfo.title}`);
    browser = await playwright.firefox.connect({
      wsEndpoint:
        `wss://cdp.browserstack.com/playwright?caps=` +
        `${encodeURIComponent(JSON.stringify(caps))}`,
        firefoxUserPrefs: {
              'dom.events.asyncClipboard.readText': true,
              'dom.events.testing.asyncClipboard': true,
            },
    });
    context = await browser.newContext(testInfo.project.use);
  context = await browser.newContext()
  page = await context.newPage();

  await page.goto(`${url}/form`)
  await page.waitForTimeout(15000)

});

This is in my projects:

    {
      name: "playwright-firefox@latest:OSX Ventura@browserstack",
      use: {
        launchOptions: {
          firefoxUserPrefs: {
            'dom.events.asyncClipboard.readText': true,
            'dom.events.testing.asyncClipboard': true,
          },
        }
      },
    },

However, when I use this to launch the browser:

  browser = await firefox.launch({
    firefoxUserPrefs: {
      'dom.events.asyncClipboard.readText': true,
      'dom.events.testing.asyncClipboard': true,
    },
  })

the function reading from the clipboard works without a hitch. However, this method does not allow me to connect to Browserstack, even when I set a corresponding cdpEndpoint in projects.

Why is this happening? How can I both connect to Browserstack and read from my clipboard?