I recently transferred 0.01 ETH from Coinbase to Bittrex. I assumed this would be a simple one hop transfer with a single gas cost. However, after reviewing the transfer, it looks like there was an internal transaction that acted as another point in the transfer, and I was charged an additional gas cost between that point and the Bittrex wallet. Why did this happen?
Additionally, the cumulative price of these two transactions was ~0.001295 ETH, but the final value deposited in my Bittrex wallet was 0.00655876, well below the initial transfer amount (0.01 ETH) minus the two gas costs. What am I missing? Where did the extra ~0.00215 ETH go?