Unusual Payment Splits

[Brian]

Suse 9.2 Gnucash 1.8.8
New to the list. Not sure if this has been covered before. While browsing my
checking account I noticed some unusual things against many payments shown
in the register. I refer to payments for invoices issued as a service business. 
These payments showed splits. Upon expanding the splits I noticed the payment
broken down into small sub amounts. For example.
The top line Deposit $3
Second line Payment Checking account $3
Third line Payment Accounts Receivable $2
Fourth line Payment Accounts Receivable $1

They all balanced.

Not sure how this came about. The invoice was $3 payment $3.
I wonder if it was something to do with the way I was putting in payments ?

Any ideas ?

Brian