If you change an attachedEntity position with:

InventoryStorageSlot.SetAdditiveTransformLS(vector);
or:
InventoryStorageSlot.OverrideTransformLS(vector);

The new position will not updated/set in "SCR_InventoryMenuUI / ItemPreviewManagerEntity".

So if you open the Inventory or weapon inspection, the Entity is still on the wrong position. But in the main world, the position is updated correctly.