a corrupt wall graphic representation in section view (ac12)

[Anonymous]

hi,
i have a wall which looks corrupt in the section view. a similar wall displays a selection with its full thickness, my wall is only a portion of its thickness.
copying and pasting attributes from the 'healthy' wall to the corrupt one doesn't work.
removing all seo operations for this wall object doesn't work either. no rebuilding gives back the appearance (which was ok a few months ago).

the corrupt wall behaves properly in the plan view.

moving this wall outside of the building (i refer here to the section view) strips it of all handles, only openings are visible and selectable. i have no clue what has damaged the wall in this way.
can anybody help?
thx in advance,
rob

[Anonymous]

old appearance of the corrupt wall...
rob

[Anonymous]

and a healthy wall...
rob

[Anonymous]

i've just discovered that the wall is empty in 3d, except for the door and windows. a real ghost wall.
(it's an 11 storey building: 2 below, 9 above ground, so i rarely do a 3d preview due to its time consuming workout.)

so i tend to use the other wall to reproduce the corrupt one. it would be fine to know what was the cause, but it doesn't seem easy to find out.
rob