John, that a GOOD question - and I'm sure you're not the only one who has this problem.
Flora 
is quite right, the history state that you were using before was linked to the image as it was when you originally opened it
(and which now resides on the background layer) and does not get saved in the PSD file. When you opened the image the second time, the history state that it
now remembers is the present state of your work,
which will include your new AHB layer - and this history state is what it will use as the base for cloning.
Here's my workaround
(maybe someone knows a better way):
- Turn off your AHB and White layer (now you just see the original image);
- Duplicate (Image>Duplicate or right-click on the images toolbar), and mark the option "Duplicate Merged Layers Only". This makes a clean image with the history state pointing to the right place.
- We are now going to copy white and AHB layers. With both the new and old images on screen, select the old. Press <Shift>* and click and drag the white layer to somewhere in your new image. Repeat with the AHB layer.
- OK, resume fun with AHB!
*This ensures that the layer gets lined-up properly
Rô