problem using PayFlow Pro

We are using ProductCart  v3.51b  with Payflow Pro.

For a small percentage of orders.   In the invoice, Payment Method box, there is no Transaction ID, and no Authorization Code.  The order is shown as paid (green flag) in the ProductCart control panel . However, there is not record of the transation in the paypal payflow account.

Does anyone have any idea what might be the problem.  I think about 12 - 15% of the orders never get charged, but shows up in ProductCart as paid.

I did upgrade to Payflow SDK .net v4.31 last month,  but I don't think that's the issue, because the problem existed before and after the upgrade.

Thanks!

We have similar things happening with regular paypal.  Sometimes the customer pays and it does not shows as being paid in PC, and sometimes just like what you have.  I would say it is less then a percent in our case, and we are not to concerned.  We print all invoices, then we log into paypal, and make sure it is there.  Then we stamp the orders as paid and they get shipped.  We do the same with Virtual Merchant, and sometimes have double payments there from customers who simply double click.  We fix it and mark the orders as being paid and ship them.  

Quite honest I don't think it is PC.  I think it is a paypal latency for not reporting back to pc.  At least when we have payments in paypal that are not reported in pc.  This one will be very hard to track down by anybody without any error messages.  As I've stated it happens very seldom, so we don't bother.  It is also a good accounting practice to cross check both sides before shipping.  You may want to raise the trouble ticket with EI.  They are really good in finding errors and always provide fixes in a very short time.    It may be a small issue caused by your provider's server, which they cannot foresee when coming out with their product.  I had that once, and again they found and fixed it within a really short time period.  It can be tricky when so many providers are involved.