differrent date between AP Credit Memo and Journal Entry

Hi!

I don't know why AP Credit Memo posting date = '31/08/2011' but Journal Entry record posting date ='1/9/2011'.

Change log on AP Credit Memo Create date ='31/08/2011' and change log on Journal Entry Create date='1/9/2011'

APCredit Memo and Journal Entry link together.

I try to make AP Credit Memo again and check. It's ok. It's not always happen just 1 Entry has problem.

pls help me solve this problem