Hi,
you are online, perfect - I will try to explain the issue in this case.
1. AutoCAD detects some errors with 23 boundary objects
(Open file by RECOVER command, hit [F2])
Yes, you can do nothing and you can't change that at first, but it's good to know.
I also recommend solving bugs that you know.
(recover / audit and fix what is to fix)
2. The hatch is still there (you can see they are 402 objects)
and visible, but not in expected shape.
I've been thinking for a long time how I can show you the thing and
think I found a way.
3. Go into K1.dwg
Copy this hatch to the side,
-you can see one enclosed island-
select it and use hatchgenerateboundary, delete the hatch
-you can see 2 polylines, one for the outer boundary, one for the island-
And now I will show you the data error of this hatch object!
Your current pickstyle is set to select associated hatchs only (without there assoc.boundaries),
turn on your assoc-Hatch pickstyle now, please.
(type in PICKSTYLE and change the <current value> to <current value + 2>, means from 0 to 2, or from 1 to 3)
With Pickstyle 1 or 3 you select assoc.hatchs incl. there boundary object.
Pick the hatch in K1.dwg, and see the grips, also the information in properties palette!
You can see: Just ONE Polyline (the one of the island)
And that's it!
The hatch shape you can see doesn't match the information about there associated boundary objects!
corrupt data..
And now, back to your result (pasteorig the hatchs into the other file) and take a look here:

And if you force a recalculation of this hatch in K1.dwg, you can see the problem in K1.dwg without copy/paste too!
Select the hatch. click the grip to make the grip hot and drag the point to...the same point!
After this step, the hatch/data is fixed, looks different to what you want, but the data is right now.
SideNote: I reproduced the issue with PASTEORIG, but not with PASTECLIP
Workaround would be: Use copyBASE instead of copyclip and basepoint 0,0,0
use pasteclip 0,0,0 instead of pasteorig.
But again: If you go this workaround, the hatch looks fine, but there is still a data problem!!
I case of "fail" (your way with pasteorig) , the hatch shape is the right then!
Hatch data matchs hatch shape then.