Disable "present" for frames outside a Prototype Flow

Once a Prototype flow is defined by a Starting point, Figma will show only these flows in the prototype when clicking the “Present” button. So far, so good.

However, if one selects a frame outside any flow and clicks “present”, this frame becomes visible in the prototype, as if it was part of the 1st flow.

To me, this is unexpected behaviour: I’d even consider it a bug, but I couldn’t find the category [Prototyping / Bugs] in the Forum.

Ideally, I’d suggest that, by default, once a flow is created, only the frames inside that flow are visible in the prototype, no matter if other frames are selected or not.

In time: locking all the frames outside a flow is not much user friendly and it would block Developers from inspecting them.

Is there an alternative to overcome this already?