In the Offset Curve filter, when Make Stroke is ticked, I can change the percentage in the Position field to dictate how much of the new stroke is outside the original contour and how much inside.
If I untick the Make Stroke box to get a single offset contour, I notice that the Position gets greyed out as I’d expect (since it would seem to be irrelevant). But: the percentage still affects the position of the added curve. In fact, if I turn on Make Stroke and set Position to 100% and then turn it off, I find that the offset curve filter does nothing (since the filter is essentially deleting the other curve that actually moves off the original contour).
This is quite confusing since at 100% the filter does nothing, but I would say it would make more sense to me to have the filter, when unchecked, do what it presently does with Position 0% rather than be affected by the Position at all.
This is on Glyphs 3.0.2 (3052)