React-Native webview component not persisting cookies in Auth0 hosted page

[HarryLincoln]

Background:

I have a GTM (with Tealium) script placed in the head of an auth0 hosted page.

This auth0 hosted page is called from a Web client, and a React Native client - both using auth0's sdk method webAuth.authorize().

Call from Web client (expected behaviour):

• User auths from client
• redirect to hosted auth0 page
• GTM inited and fires some events

👌

The cookies look good and are persisting here.

Call from React Native client (no cookies present in WebView redirect):

• User auths from client
• Webview component pops in-built browser to sign in, navigating to the same auth0 page
• no cookies are present (none at all)
• GTM does not fire

👎

Versions of deps:

• ios version: "12.1"
• react-native-webview: "^8.0.4"
• react-native: "0.63.3"
• react-native-auth0: "^2.6.0"

What the React-Native WebView component looks like:

<WebView
    ref={webViewRef}
    source={{ uri: source }}
    sharedCookiesEnabled
    thirdPartyCookiesEnabled
    domStorageEnabled
  />

Checks:

• Standard Safari settings to enable third-party cookies

Thoughts:

There must be something wrong with the WebView?