I've not had such experience because I am extremely careful to copy my seed phrase after creating my wallet. I joined the Bitcoin community when Bitcoin was already being treated as a digital gold and a very valuable asset and their was not time to mess around and be careless with handling my secret key. The only case I have heard from friends is that their fund was being transfered to an unknown wallet without h
Their consent. When they discovered they lost their coins, there was no way to get it back.