Actions: Redirect After Submit

Case:
I have an edit post form and whatever I set as an action to redirect, it takes the Query Key post_id and puts it behind the redirected URL.
I downgraded the plugin and WordPress, also deactivated all my plugins to test if it works, without results.

I am on:
https://data-for-good.com/update-project-progress/?post_id=15267

And when I update you need to go to:
https://data-for-good.com/my-dashboard/

But I get redirected to:
https://data-for-good.com/my-dashboard/?post_id=15267

As a result I get a 404-page.

The page I need help with: [log in to see the link]