ACTOB Pending Item Errors on Foreign Currency Cash Application

We are having a sporadic issue when applying payments to open item. We have a Foreign currency BU that contains Open Items in MXN and USD entry currencies. We also receive payments in both currencies.  SOMETIMES when we build a worksheet and pay 2 or more open items with different entry currencies we get ACTOB error in AR_PGG1. It does not seem to matter if the Payment currency is USD or MXN. I Can delete the group and Rebuild the worksheet and the Items will post. This is very intermitent, I cannot get  this to occur in DEMO. Does anyone have