Here: Server Geographies | Bitwarden Help Center even though it looks like the page was written for organisations to migrate between the US and EU servers, there is the idea that individuals can export their vaults and import it on the other server. While it isn’t explicitly said that everything WILL be migrated over without being changed, there is also nothing said about what WON’T be - the creation and updated time metadata (I think the times for the passwords in password history are also changed). But I found out the hard way after migrating my own vault from the US server to the EU server and only realized this later, at which point I eventually migrated back.
Even though the exported vault file DOES contain the correct times, when you import them to your account both of those just get set to the time at which you imported the vault for every entry. I do not understand why this is the case. If the rationale was to make clear that importing the vault was its own update, why not just change the “updated” time and leave the creation time as it was before? Or give an option to keep the times as they were, or add another field for import time to avoid changing the others? It’s not like I imported from another provider - this is Bitwarden to Bitwarden using the json format.
As is this data is lost and you might not realize it until it is too late. Thankfully I didn’t delete my account on the other server post migration, or I simply would have to accept that those times are gone.
If you’re going to keep this functionality as is, I suggest that it is at least written somewhere in the documentation for importing vaults or migrating that these times will NOT be migrated so that users are aware of what is lost if they choose to do so.