If you are totally sure you don't know that address, then it almost seems like you used a malicious client.
Do you remember where you downloaded Electrum? Did you verify the signature of the download?
Have you used mybtgwallet or claimed forked coins lately?
The 2.0551166BTC that got sent to 1BfzVjwQAouUEBNMU4xStTLqMMkbin15kM got immediately forward to 157WDeAU3LvWopxR4hQXnxUzxpcq1LFE4H. Script-sweep like behaviour.
I downloaded that coin from the original site just like anyone else
And I kept funds on this wallet for weeks nothing happened
What happened is I sent two transactions with low fees then I tried to increase fees then signed and broadcasting both transactions then closed my internet
Back after few hours find that the 3 transactions happened in same time and same second
I already have the coins unconfirmed on my wallet but in same time there is a confirmed transactions sent to unknown address
Maybe this funds sent to block or anything like that and instead I got unconfirmed coins on my wallet ?
The question is hacker has the time to steal it whey he stole it in the time I'm sending my coins
Btw the money transferred like 3 times to different wallets I own it all but the last one I do not own
Also the other question is why I gave the coins but not confirmed? Is it fake ?
I mean as long as you didn't verify the signature of the download, it may have been compromised.
Anyway.
Both transactions are real, but the first transaction will never confirm, as it is already double spend.