indeed we have been on the subject since this morning, it seems to be a bug on Vinted’s part.
We are continuing to investigate to best understand what is happening.
In case you need it, a little info: I tried to re-list all of this on the afternoon of the 29th. The first keychain went through, and it was from the second one onwards that I was banned for 24 hours. My ban was lifted just now around 1:45 p.m., so we can say that the Vinted bug definitely started after 2 p.m. yesterday.