"You consider unconfirmed coins when creating a transaction, but you do not account for the size of their ancestors. This can lead to largely underestimating the fees for the transaction, and to reporting a largely overestimated feerate to the user."
"You consider unconfirmed coins when creating a transaction, but you do not account for the size of their ancestors. This can lead to largely underestimating the fees for the transaction, and to reporting a largely overestimated feerate to the user."