Thrusection goes beyond the intended range

Hi all,
I am trying to create a face by BRepOffsetAPI_Thrusection, using 5 wires (The wires are not closed).

All the wires are reparametrized from 0 to 1, so that the thrusection happens smoothly across the 5 wires.

However, when I use the API, the face goes beyond the upmost and bottom-most wires used. You can see it in the picture attached.

I assumed at least 1 wire has a different orientation relative to others, therefore I checked the orientation but all have the same orientation.

What may be the cause of this distorted shape? I have added the wires in order as well.

Thank you!

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