I also randomly find some small amount of TRX and BTT on sending TRX or any tokens to and from my wallet. Not just binance, a few days ago, I sent some tron from my tronlink wallet to one exchange (ftx) and received the tron and after some moment, I received another small payment of 0.000002 Tron. No idea how it all works maybe they are some sort of fees cashback schemes or something.