Differences in Months Ammount Running AFBP

Hi Gurus

I´m running AFBP but I have found a difference...

Total result for March is 268.551.515

But when I see april .... the total for march is now  268.539.412

I have found a difference of 12.103 and I was able to identify which asset is...Now How come this difference happen?
Waht should I check ?

For your inputs

thanks

jose