TypeError: c.links[1].walkedPath.pathContext.bezierData is undefined for combineUnion on EllipticArc and Rectangle

Below are sections of my code causing issues. offset and width are variables with numerical values.

const botArc = new makerjs.models.EllipticArc(180, 0, width / 2, 25);
const botArcMoved = makerjs.model.moveRelative(botArc, [
      width / 2 + offset,
      offset,
]);

let box = new makerjs.models.Rectangle(100, 50);
box.origin = [0, 0];

let model = {
      ...
      models: {
      ...
        valve: makerjs.model.combineUnion(botArcMoved, box),
      },
};

If I comment out valve: makerjs.model.combineUnion(botArcMoved, box) the code doesn't give me the type error and the rest of the models and lines are drawn correctly.

Doing this kind of combine also is giving me an error:
makerjs.model.combine(botArcMoved, box, false, true, true, false).

No source file, test, or entry point is named. Start by reproducing the supplied EllipticArc and Rectangle examples with combineUnion and combine, then trace the failing geometry operation. Done means both combinations no longer raise the reported TypeError for this case.