Nothing caused, I was just seeing people complaining so I thought I'd delay getting an extension.
It's irrelevant now since I got the extension already and nothing got wiped out. All good.
Should be safe!
It's always safer to have backups of your settings (like at https://metadata.nostr.com/ )
What client did cause this to you?
Discussion
Extension by itself will not wipe anything ;) Careful with clicks!