We've noticed an issue in POA. Wondering if anyone else has seen this?

When invoicing an existing receipt that contains 2 vendors, we can add misc charges to the second vendor without any issues as long as there is no proration and if the receipt lists the lines to the first vendor first and second vendor at the bottom of the receipt.

If however there are lines to the first vendor, then lines to the second vendor, then more item lines to the first vendor on the receipt, we cannot add misc charges to the second vendor unless we delete the bottom lines to the first vendor.

Are we doing everything right? If that's the case, I guess we should always recieve all lines for one vendor first, then the second vendor, and never go back and forth from vendor to vendor.