The UA Mage of Lorehold's Ancient Companion (Healer) has the Healer's Light action; do those temp HP remain if you bond to a different spirit type?

Question

In the UA of Mages of Strixhaven, the Mage of Lorehold's Ancient Companion feature lets you bond to a spirit when you finish a short or long rest, choosing Healer, Sage, or Warrior.

If Healer is chosen, the Ancient Companion has the following action:

Healer’s Light (Healer Only). The companion chooses a creature it can see within 15 feet of itself and flares with invigorating light. The creature gains 1d8 + PB temporary hit points.

When you use a short rest to bond to a different type of Ancient Companion spirit (Sage or Warrior), do the temporary HP remain on whomever they were given to?

Answer 1

The temporary hit points would remain

They would remain, as per the general rules for temporary hit points. These are given in chapter 9 of the Player’s Handbook and Basic Rules, at the end of the section on damage and healing. The very last paragraph about temporary hit points states:

Unless a feature that grants you temporary hit points has a duration, they last until they're depleted or you finish a long rest.

This feature does not list a duration, so the temporary hit points last until the target loses them (by taking damage) or finishes a long rest.