[mlondon] “I also tried the 7Mbps preset which gives me a smaller file, but the preset is 1-pass – I want to use 2-pass, and the preset is bottom (lower) field and my source material is PAL 10bit uncompressed which is upper field.
I made my custom settings by duplicating the preset and changing the data rates, passes and field order.”
Assuming that’s all you changed in the preset, the clues are going to 2 Pass encoding and changing the field from Bottom First to Top First.
Frame type defaults to Progressive. Did you leave that as is or changed that to Interlace?
Are you using Frame Rate and/or Resize filter or any others?
I don’t have any PAL 10 Bit Uncompressed to test with but I can arrange FTP access for you to upload a Gig or two for me to test with. Yes, that’s small relative to an 83 minute project but it might give me a clue.