X-REFs not aligning...(super strange bug?)

[GPK]

Hello CAD Gurus, I've got a real head scratcher for you....

 

I have 3 drawings (.dwg), a master and a utility drawing, and a site drawing. The master has the utility and site attached as an x-ref overlay (assume all references are attached at 0,0,0, with scale factor 1, we've had multiple very experienced CAD users checking all this). The issue just started recently where the utility dwg is not lining up with the site dwg while both are attached in the master dwg. It all used to line up fine but now suddenly the utility dwg needs to be moved about 500 units east and 800 units north to line up. You can tell its not scaled wrong because the size of structures and length of pipes is still correct.

Here is the really freaky part, if you copy by base point (ctrl+shift+c > 0,0,) a line from the utility dwg then paste it in either the master or site (ctrl+v > 0,0) it pastes in exactly where it should, lining up with the site. EVEN while the utility xref is sitting there with its base point at 0,0,0 and scale at 1 and yet some how a few hundred units away from lining up to the site. So copying an object from the utility and pasting it in the master lines it up but, xref-ing the utility and it doesn't line up. Additional info. about the strangeness of this. If you attach the site dwg to the utility drawing everything lines up, HOWEVER, if you attach the utility dwg to the site its off by the same amount that it is in the master.

 

Before offering advice please see our troubleshooting list below.

(each of these settings has been double checked by 3 different people in my office, none of us are cad newbies)

There is no GEO location on any of them and no transformation (from that one tab in drawing settings)

The units (DDUNITS) and the units in the drawing setting tab of the toolspace panel are the same in each drawing.

The UCS is set to world in all 3 drawings.

The insertion point of each and every XREF is 0,0,0

All XREFs have 1.0 scaling (no scaling)

All drawings were made from the same version of CAD (2021 I think)

Its been audited, purged (regapps purged too), saved, closed and reopened by another guy on another workstation yet the problem persists.

We tried detaching and re-attaching everything.

 

Is the drawing just broken or am I missing something obvious? Heck maybe I'm missing something not obvious! Whatever the case any help would be much appreciated.