As I can't appear to reply to the posts already on this subject, I'm having to create my own.
There is a massive issue at the moment on the app and the website. I had it yesterday and thought it was a one off with a user, now its happening today as well. On Android I cleared out the cache thinking it might be that but made no difference.
Buyers that are buying my items, if I click on their user name I get:
Sorry, this user was not found.
Yesterday when it happened I looked again a few hours later, the user was now found.
I've had someone buy an item and its saying the user can't be found.
Ebay doesn't appear to have acknowledged this bug yet. I've seen 2 other people post about it.