wrong rendering of glb/gltf object

hi,
I implemented vr krpano plugin in exiting krpano virtual tour.
I successfully imported two 3d objects in glb and glft formats.
At first glance they are rendered properly
(see problem1.png)

But if then I move around the panorama, some segment of the 3d object disappear.
We already tried to merge all the layers, but and save a single block, but in this case the object is not rendered at all.
(see problem2.png)

yes.
I don't know hot to delete that message.

We started from a Krpano sample template, using plugin "three.krpanoplugin"
We imported several three.js version that works correctly standalone but not inside a krpano virtual tour.
At first glance, the 3d object (GLTF format) are correctly rendered, but when I move around the scene, objects disappear.

I also tried to use the latest threejs plugins:
https://cdn.jsdelivr.net/npm/three@0.141.0/build/

but the issue is still there.
I checked other krpano forum posts, and it seems a common issue:
https://krpano.com/forum/wbb/index.php?page=Thread&threadID=12479&pageNo=4[/size]

[size=10]Some hints?
Regards.