Today when i started using my glowforge my cut was pretty far off where it should be. So, i used another piece of wood and positioned it where the edge did not matter. As you can see by the pic my print is now 3/4 of an inch off left and right, but pretty much on track top and bottom. Ever since I have had my GF the cut has been pretty much 1/8 of an inch off and i just use the ruler to position my material accordingly. This is right under the center camera, it gets worse further toward the edge.
You did not bump the head after the initial calibration. That will definitely throw it off. If so, just turn off the GF and turn it on again to force a recalibration.
Your material thickness setting is correct (check with a caliper, a small error here makes a huge difference in the camera placement accuracy), or use Set Focus (under the Gear Icon) to set the focus in the area on the material where you want to place the operation.
After doing all that it said no improvements were made, unable to calibrate further. But, when i did another print it was back to 1/8 inch offset only which I am used to… so it somehow corrected itself.