Summary: How to keep payments for owner's with multiple accounts from auto-splitting when received through the lock-box.
If an owner with multiple accounts sends a check to the lockbox that is intended to be applied to a specific account but the check gets split between multiple accounts, this indicates that the system is set to auto-split payments that are received to the account.
This can be adjusted by going to Settings > Interfaces screen then find the bank to where the payments which are auto-splitting are being received. From there select Edit on the Auto Split Payments line.
Then uncheck the box beside Auto Split Payments.
Now when a payment is received for an owner with multiple accounts, the payment should only be applied to the account the owner specifies.