Creating new public instances via "Invite Me" to private worlds seems unintended, because neither the VRChat Client (2025.4.2, build 1768) nor website allow creating public instances of private worlds.
Reproduction: Create a new group or grab an existing group's ID (I used a now-deleted grp_6102d838-c02d-44d2-a953-0c2211d025ab). Grab a world's ID. Craft an unlocked invite URL manually by hand. Invite yourself with "Invite Me" to create a public instance.
The API should've disallowed creating public/group public instances of private worlds, or both the VRChat client & website should allow this behavior.