Signs you or someone else has switched from a parallel universe

-Someone you have never met claims to have encountered you in a place you have never been
- You notice a shop you have never seen before and the owner say they have been there for years
- A person in a vacation resort you see for the first time claims you were there before - A sibling or friend recollection of a past event is curiously at odds with what you remember -In a bookshop you notice the book of an Author you have never heard before...and turns out to be a major writr in your favourite genre who has already published many books