Yes
Monzo won’t know that the transaction’s been made so you won’t receive a notification & your balance won’t be updated. Monzo’s the issuer mentioned in the below, from the blog
The first the Issuer sees of this payment is in the “Presentment” file, which may be a day or two later.
That’s why I’ve requested this feature -
so that the user can keep a record that the payment’s due to be taken & hopefully make Monzo aware of that + deduct the pending transaction amount from their balance etc.
Please do post a comment / like the post there if you think that would be useful too - so that Monzo can see you need it.