Thanks DC
Advanced codec settings: (default with curve aggression set to 'Slow')
Curve Compression:
Scaling Mode: Alternative
High distance from Average: 0% (greyed out)
Low distance from Average: 0% (greyed out)
Auto. Calculation (Checked) Light
Max. Overflow Improvement: 50%
Max. Overflow Degradation: 50%
Bitrate Playback Delay: 250 frm
Cruve Agression: Slow
In loop Filter:
Inloop Cutoff Quantizer: 11 (greyed out)
Auto. Select Best Quantizer (Checked)
Pre-Filters:
Enable DropDupe (Unchecked)
Enable BlackFilter (Unchecked)
I've attached the .task file for this as well.