Let me summarize all the findings of this thread for future reference:
So, under normal circumstances, the sub-elements or components of Railings (such as Handrail, Post, Balusters, etc.) can be displayed with their own Pen in 3D and Sections/Elevations. It is usually set by the "Contour Pen" setting in the "3D Representation" panel of the component GDL Object's settings.
So what may cause the View Pens of Railings to change in Sections/Elevations from their Pen set in the Settings Dialog (1., 2., and 3. below apply to other element types, 4. applies only to Railings):
1. If you go to the "Elevation Settings" Dialog, and in the "Model Display" panel, check the "Uniform Pen for Uncut Elements" checkbox, all view lines of the Railing that are not cut by the Section/Elevation will be overridden with the specified Pen. Please note that all uncut lines of all other elements will also be overridden so the change is quite visible:
2. You might have a Graphic Override active that overrides the Line Pen of the Railing. This will again affect the whole of the Railing.
3. Renovation Filters can also override the Pen of the whole Railing element. In the below example, the Railing is set to the "New" Renovation Status. and the "00 Show All Elements" Renovation Filter specifies New Elements to be overridden by a red Pen.
It is worth noting that in case an element is overridden by both Graphic Overrides and Renovation Filters, Graphic Overrides will be stronger.
4. If you go to the "Model View Options" Dialog, and in the "Railing Options" panel, set the "Railing 3D and Section/Elevation" field to "Simplified", the whole Railing again will be overridden. In this case, you may also see some parts of the Railing not generated due to the simplification of its geometry.
If all the above do not solve this issue, then it is really possible that the Railing geometry is corrupted somehow. In that case, you can try to delete the Railing and redo it.
If even redoing the Railing does not solve the problem, you may try to apply another Favorite and redo the Railing, since it may be the Favorites data that was corrupted, and applying another Favorite might fix this corruption.
If even that does not solve it, you may try to use the "Open and Repair" option when opening the file, it may fix that.
If even that does not fix it, then it may be file corruption. In that case, I would report this to your local support.
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