My path hiccups

Whiel trying to make a board game, i dynamically generated a path in script. It worked really, really well as long as the object kept moving around the path. But when i set it to just move once, i had problems

i *think* the way to do this is to set the number of loops to 1. Here's the code:

//--- Args: obj, speed, isForward, startNode, endNode, followMode, loops
mainPath.attachObject(ship, 30, 1, %start, %end, "WRAP", 1);

i also tried this using the per-field commands (setEndNode, setLoops, etc.)

It looks like things are going to work - my object moves from start node to end node. Then 2-5 seconds later (at random), the object backs up a node and then tries it again. And again. And again. Totally at random. It looks like my object is hiccuping. Occassionally TGB dies from a buffer overflow heart attack

This is on a near-blank test level. There is no collision. Other than the object on the path, nothing is moving. The console shows nothing

i can't find a lot of documentation on this. i did find mention of an event called onUpdatePath but it never gets called for my object, so my debug info there doesn't help me

Anyone have any ideas?

Full code:

function initVariables()
{
	if (isObject(mainPath))
	{
		mainPath.clear();
		mainPath.safeDelete();
	}
}

function buildPath()
{
	if (isObject(mainPath)) error("how 'come mainPath already exists?");
	new t2dPath(mainPath) {
		//--- Do i need to add this to the scenegraph? Yes
		scenegraph = sceneWindow2D.getSceneGraph();
		pathType = "CATMULL";
	};
	
	mainPath.addNode(startingBlock.getPosition(), 0);
	for (%i=1; %i < $numberOfTiles; %i++)
	{
		%tile = $tiles[%i];
		mainPath.addNode(%tile.getPosition(), %i);
	}
	mainPath.setDebugOn(1);
}
function moveShip(%start, %end)
{
	//--- obj, speed, isForward, startNode, endNode, followMode, loops, sendToStart
	//--- FollowMode = wrap, reverse, restart
/*	mainPath.attachObject(ship, 0);
	mainPath.setStartNode(ship, %start);
	mainPath.setEndNode(ship, %end);
	mainPath.setOrient(ship, false);
	mainPath.setSpeed(ship, 30);
//	mainPath.setMoveForward(ship, true);
	mainPath.setLoops(ship, 1);
*/
	mainPath.attachObject(ship, 30, 1, %start, %end, "WRAP", 1);

	//--- Hickups on last node :(
	
	echo("loops = " @ mainPath.getLoops(ship));	
	echo("end node = " @ mainPath.getEndNode(ship));	
}