We recently discovered that new Peridot players are incorrectly being prompted to create a Keeper name when they already had an existing Niantic ID. For context, Keeper names are now powered by Niantic ID. If you had an existing Niantic ID and then created a Keeper name, your Niantic ID may have been overwritten.
Our team is working on this issue and plan to have it fixed for new players as soon as possible. If this occurred to you, please reach out to us via in-app support so that we can fix your Niantic ID.
-The Peridot Team