K40 doesn't re-acquire last position after home/origin

Hello everyone. I’m brand new. Got my K40 Mini from eBay a few weeks ago and decided to upgrade to Cohesion3D/Lightburn/Camera. I’ve been reading and watching videos every day for several days in order to educate myself and hit the ground running.

The new controller board arrived today. I’d been messing around with Lightburn and the tutorials, so that was already set up and ready to go. I haven’t installed the camera yet. First thing I was interested in was checking basic functionality. Unfortunately, there’s some weird stuff that seems to be happening. If I set up a job using absolute coordinates, I was under the impression that I could home the laser or send it to the origin and it would start a job at the same x and y position, as long as I didn’t move the image on the grid in Lightburn.

But this doesn’t happen. My stuff doesn’t line up. The whole job moves about 10 mm to the left or right after another job is started. I’m not sure what the rhyme or reason is and I have to do more experimenting, but things are definitely moving. Also - and this is weird - I set up a straight cut and executed it, then turned my laser power down below the threshold of forward-biasing it and the start/finish points MOVED! What on earth would the power setting on the machine have to do with positioning?

My cutting is fine - I’m not getting any weird results, do it’s not like the belt is jumping or anything. And I removed the new controller board from the chassis, as I remember reading that grounding it might not always be a good idea, due to issues with the k40’s power supply - but that didn’t help.

I was trying to get the whole thing dialed in before I leave town tomorrow, so I won’t be able to get to the machine for a couple of weeks, but I’m hoping to work this out quickly when I return, so any input would be appreciated!

Edit: I’m watching this video: Lightburn 101 - Starting Position, Origins, and Homing - YouTube and hoping I figure this out.