Hello SandorToaso
This looks a bit strange! Did you try moving one of the outlets as shown in the tutorial video and did the fluid volume get updated automatically in this case?
Can you go to the Structure tree (located on top right side), then expand the Volume component, right-click on Volume body and select "Update Volume Body as Created" and see if that helps to update the fluid domain? Refer below image.
You are navigating away from the AIS Discovery experience