Updating coordinates for a moving libGDX object

I have a number of TextButtons I can drag, checking if they overlap an Image when I let go. Currently what I'm experiencing is either a particular object will detect collision located anywhere on screen, or it will never collide. Note that I'm not using the native DragAndDrop class, but have adapted a parallel implementation from a book.

Given that my TextButtons move when I drag them, I think the following function is updating the (x,y) of the object:

public void touchDragged(InputEvent event, float eventOffsetX, float eventOffsetY, int pointer) 
    {
        float deltaX = eventOffsetX - grabOffsetX;
        float deltaY = eventOffsetY - grabOffsetY;
    a.moveBy(deltaX, deltaY);
}

Is that correct that the Actor a's x, y change due to moveBy? Because my latter collision detection - where I examine the dragged objects coordinates - reports the same x,y coordinates for the dragged object no matter where I release it. Here's the log for releasing the object from two different locations on the screen:

Does (626.8995, 393.1301)(923.8995, 393.1301)(923.8995, 499.1301)(626.8995, 499.1301) fit into (610.0, 256.0)(990.0, 256.0)(990.0, 677.0)(610.0, 677.0)? 
Does (626.8995, 393.1301)(923.8995, 393.1301)(923.8995, 499.1301)(626.8995, 499.1301) fit into (610.0, 256.0)(990.0, 256.0)(990.0, 677.0)(610.0, 677.0)?

and here's the collision detection and sys out generating those log messages:

//this is called by the dragged obj, a, on touchUp() against each of the targets
public boolean overlaps(Actor other)
{
	//a is the first, dragged object, other is the target
	if (poly1 == null)
		poly1 = getPolygon(a); 
    Polygon poly2 = getPolygon(other); 

    
    float[] p1v = poly1.getVertices();
    StringBuilder sb = new StringBuilder();
    for (int i=0; i<p1v.length-1; i+=2)
    	sb.append("(").append(p1v[i]).append(", ").append(p1v[i+1]).append(")");
    float[] p2v = poly2.getVertices();
    StringBuilder sb2 = new StringBuilder();
    for (int i=0; i<p2v.length-1; i+=2)
    	sb2.append("(").append(p2v[i]).append(", ").append(p2v[i+1]).append(")");
    System.out.println("Does " + sb + " fit into " + sb2 + "?");
    
    // initial test to improve performance
    if ( !poly1.getBoundingRectangle().overlaps(poly2.getBoundingRectangle()) )
        return false;

    return Intersector.overlapConvexPolygons( poly1, poly2 );
}

public Polygon getPolygon(Actor a) {
	Polygon p = new Polygon();
//    	float[] vertex = { a.getOriginX(), a.getOriginY(), a.getOriginX(), a.getY(), a.getX(), a.getY(), a.getX(), a.getOriginY() };//new float[8];
//    	float[] vertex = { 0, 0,    a.getWidth(), 0,     a.getWidth(), a.getHeight(),     0, a.getHeight()};
    	float[] vertex = { a.getX(), a.getY(),    (a.getX() + a.getWidth()), a.getY(),     (a.getX() + a.getWidth()), (a.getY() + a.getHeight()),     a.getX(), (a.getY() + a.getHeight())};
    	p.setVertices(vertex);
   // 	p.setPosition(a.getX(), a.getY());
    	//p.setOrigin(a.getOriginX(), a.getOriginY());
    	return p;
    }

There are a HORDE of collision detection posts already on StackOverflow, and they helped some in showing me how to form valid polygons. Perhaps the 3rd party drag and drop is why I'm not finding my answer in the wealth of knowledge out there, but I'm leaning towards some annoying mistake I'm overlooking.

Score another one for logic failure. Originally I thought I'd just be saving the dimensions of the dragged polygon when I decided to cache it, thinking it would save a few polygon creation steps as it was checked against a number of potential targets. Later, as I kept reworking what values to feed the polygon vertices, I tied in the location of the polygon as well. So it was just caching the first place I dragged it to, and using that every time I dragged it somewhere.

Thanks for the comment, it helped me move past thinking I wasn't understanding the classes. I'm doubtful this particular mistake/resolution will ever be of use to someone else, and would be very understanding if this post is removed.