How is clipping displayed in Lightroom?

I do not understand cutting in Lightroom.

From what I understood, the shading of the shadows appears in the form of a white triangle to the left of the histogram and blue areas in the photo. In the same way, the clear outlines are represented by a white triangle to the right of the histogram and red areas in the picture.

However, in some photos, Lightroom displays blue and red areas, but white triangles are not shown in the diagram. Here is an example of a photo fragment that clearly displays a relatively large area in red and a tiny area in blue (the top of the antenna):

enter the description of the image here

For the same photo, the histogram is displayed like this:

enter the description of the image here

Remarks:

  • View > Show cut is checked. If I reduce the blacks or raise the whites, the triangles appear.

  • When I fly over the red zone, some points, but not all, are displayed. R 100 G 100 B 100% below the histogram.