Why it is expected, not a malfunction
No mirrored account can reproduce another's fills exactly. Every replication has lag, and lag has a price that compounds over many trades.
This is why a leader's public history should be read as evidence about their process, never as a prediction of your account's returns.
Past performance is not indicative of future results. Perpetual futures are leveraged instruments and carry a substantial risk of loss, including the loss of your entire position.