- Step 1: complete a mission and claim the reward, but DONT skip the stamp animation.

- Step 2: right after pressing ok spam the skip button. (on steam deck controller its Y)

- Step 3: The game will glitch out and gives you the reward times 2.

It will show an incorrect mission afterwards that is not actually active at the moment.
Simply back out and re select the activities menu to show the correct missions again.

I found this glitch myself and hopefully it will be helpful to you.