I believe the Character Generator is behaving appropriately. At first level, the Celestial subclass adds 2 spells (cure wounds, guiding bolt) to the warlock spell list, allowing you to have more choice for your known spells. I don't see any wording that indicates additional known spells (beyond the light and sacred flame cantrips).
I concur with AnotherCrappyDM. The cantrips, Light and Sacred Flame, are given in addition to the warlocks normal selection and do not count against the normal limit. The spells (as opposed to cantrips) are just expanded choices and the warlock does not get additional known spells, just more choices of what they can know. They still can only cast two spells per short rest (or 3 or 4 at higher levels), and the number of known spells does not increase.