New MID generated even with Old one instanciated in URL

Hi community,

I'm currently not able to track my visitor from my app to the webview.

I already found a lot of documentation like this one and this one. But it didn't fix my problem.

Currently, my third-party cookies are disabled (included demdex cookie) and I can't enable them. So I need to find a way to track the visitor without it.

When my user is on the app environment, a MID is generated. See the screenshot below from app context:

I achieved to save this ID in the URL when the user goes from the App context to the Webview context.

But my problem is that when the user is landing on the webview, a new MID is being generated even if the first one is instantiate in the URL.

See screenshot below from webview context:

You can see on the mid variable a new MID being generated. While the first one is stored in the URL in the g variable.

We reached Adobe customer care to learn more about that. They told us to use the method overwriteCrossDomainMCIDAndAID but it didn't help us here.

Does anyone have any suggestion?

Thank you