this might be a really stupid question, but I've been noticing that my SalesID field has not been saving correctly. The SalesID is the last field on the form.
The best way to assure the record saving is to click on the left side panel of the screen. You'll notice that before you make a change in a given record, the record indicator on the left-top of the screen is a blackened triangle. When you make any change at all, that icon turns to a pencil (the "dirty" icon). If you hit Escape, the icon changes back to a triangle, and all changes are undone. If you click on the left panel instead, the record is saved and the icon returns to the triangle. I have found that this is the most reliable way to save the record, and in fact, I have instructed my users to do exactly that when they are saving the last item in a list.