If i use these settings when exporting and import the clip Premiere Pro says that it is Upper. So as a test in Premiere Pro, go to the Project panel and click the hamburger menu to the right of the name of the panel and check Preview Area. Import your exported file and look for LFF or UFF.
I export a file for television broadcasting. The problem is that the application "MediaInfo" in the line "field order" shows "bf- first", and in the line "current field order" - "uf-first". When exporting from CC2018, the line "field order" does not appear in the description.