I created 2 wallets from my geth node for test how send transactions works, and sent some gwei to the first one from binance. I wanted to transfer ether from the first wallet to the second. I checked normal fee for transactions and set it to 16 gwei. Before sending I unlock my sender wallet. Here is a transaction command:
personal.sendTransaction({ from: "0x26b9551dd8f0c92311daa43143ec44e10953ecb3", to: "0x35264245dcbf92937d33231a3717240bec0b69c9", maxFeePerGas: "0x3B9ACA000", maxPriorityFeePerGas: "0x3B9ACA000", value: "0x90F81C5F84000" })
Transaction itself: https://etherscan.io/tx/0xb18fdbfb9f91f142e86fbe298655efda6d72cb2a8181073f5bc7f9043534df0c
After sending I checked my balance and there was 0. I open my receiver wallet in the etherscan and noticed additional 2 transactions from my receiver wallet. The first was on the next block, the last not included in a block.
First transaction: https://etherscan.io/tx/0x9b84d4a7eb3df3702e69c32532de8a6cc68d39ae9cef6cd313f19b1b22d2b4c7
Second transaction: https://etherscan.io/tx/0xb66a1c6bc1221a251b81672d5aad90e7fb42ae8734ad055800d0ab67cdeb44e8
I didn't start this transactions, and didn't sign any smart contract before. I don’t understand why all sent coins were automatically sent to an unknown address after receiving. Maybe there are some mechanisms that I don't know about?