All history is gone.

I don't recall deleting them, but all the history in the generation section has disappeared.
My profile info is still there.
I don't mind if it's gone, but are there any conditions like "it deletes after X hours" or "doing this causes it to delete"?
Or was this just a random occurrence this time?

Also, I have another inquiry.
I am logged in, but sometimes my account seems to disappear, and I have to log in again.
It’s not a big problem since I just need to paste my email address, but if this is a bug or an issue, could you please look into it? 🙏