<aside> ✅ Hit the Copy button in the upper-right corner of this code block. The formula can then be pasted in a Formula property.

</aside>

if(empty(prop("Parent Task")) and prop("Sub Seed") == true, prop("Task"), prop("Parent Task"))

Expanded

<aside> ✅ This expanded version of the formula is just for reference and learning.

</aside>

if(
  empty(
    prop(
      "Parent Task"
    )
  ) and  prop(
    "Sub Seed"
  ) =
= true,
  prop(
    "Task"
  ),
  prop(
    "Parent Task"
  )
)