Here's the full response (repo name is hidden)
{"isGuest":true,"isAuthenticated":false,"previewState":{"ref":"https://your-repo-name.prismic.io/previews/YlnVtBIAACYAucj5:YlnWZRIAACYAucwJ?websitePreviewId=XvgaCBAAACYAlTjx","title":"title-hidden","sessionType":"DRAFT","lastUpdate":1650062908513,"draftPreview":{"title":"tittle-hidden","summary":"Default","url":"https://your-repo-name.prismic.io/previews?sessionId=YlnV0RIAACEAucl7%7EXvgaCBAAACYAlTjx&documentId=XvARHBAAAInnuhuS"},"releasePreview":[]}}
We've already try clearing the cache and cookies; cross-site tracking prevention is not on, so there should be no issues with the cookies.
Cookies in headers looks alright. Here they are (values are hidden for security reasons).
Any hints on what the problem could be? My guess is that the endpoint is not behaving as expected.
I'll share the full details on private if needed.
Thanks!