Some banks take a certain amount of time before depositing checks. They claim it's for clearing purposes or to process the check. This can also occur when you are transferring money from one account to another. The money may leave your account on day 1, but not be credited to the destination account until day 4.
To track this accurately, you'll need to do some sort of workaround, as Money uses the same date on both the source and destination accounts of the transaction if you use a transfer (and you can't, or don't want to choose either date for both parts).
One way some people have dealt with this is to create a 'holding account' into which they transfer the payment out on day 1 and then transfer from this account to the destination account on day 4. Then this holding account is excluded from the reports.
Alternatively you could create two transactions, both using the same category (you will get a warning with this, saying that you are using an Expense account for a deposit, for instance). One to withdraw the money on Day 1 and the other to credit the money to the destination account on Day 4.
Keywords: clearing, delay