How to tell if a product listing leak is legitimate: It'll get taken down almost immediately after press picks up on it.
This supposed "Xiaomi Mi A2" product page leak still being up should be a big red flag that it's probably just a placeholder.
Conversation
There are now a ton of other swiss stores listing the Mi A2, including EAN etc. Importer is AG, distributor of Xiaomi products for Switzerland: alltron.ch/search?query=x