Can Cloudkill deal damage twice in a turn?

The spell Cloudkill has the following effect:

When a creature enters the spell’s area for the first time on a turn or starts its turn there, that creature must make a Constitution saving throw. The creature takes 5d8 poison damage on a failed save, or half as much damage on a successful one.

The bolded section is language shared by several spells (Moonbeam, Sleet Storm).

If a creature starts its turn in the Cloudkill (and therefore makes a save/takes the damage), runs out of it, then runs back in, will it need to make another save?

i.e. does “enters the spell’s area for the first time on a turn” mean:

  1. The first instance of transitioning from outside the spell’s area to inside it on a turn (yes, the creature must make the save)
  2. Any time the creature enters the spell’s area and has not previously been in it this turn (no, the creature doesn’t make the save)