When you create a Monero (XMR) deposit address under your Kraken account you are generating what’s called an Integrated Address. This Integrated Address contains a Payment ID at the very end, which is used to determine what account a given transaction should be sent to. This extra piece of information but must be included when sending a Monero transaction to your Kraken account.
Most XMR wallets support integrated address, so there should be no need to remove or alter the integrated address when sending an XMR deposit. Leaving out the Payment ID will lead to significant delays in crediting the transaction to your account, and can be irretrievable in certain cases.
For more information on Monero (XMR) Integrated Addresses and Payment IDs, see the following resources: