Bitkub normally collects a transaction fee in each coin withdrawal transaction. You can check the withdrawal fee of each coin here.
However, if your transaction is between Bitkub accounts eg. Bitkub account A transfers a Bitcoin to Bitkub account B, you will not be collected the coin withdrawal fee. You may still notice that your application or website still displays the withdrawal fee as usual while making internal transfer transactions but the fee will not be included when the transaction is completed.
Remark: The withdrawal fee will still be applied for DOT, NEAR, KSM, BAND, and SCRT internal transfer until further notice.