Expected result: the shading is always displayed as it is applied in the settings.

Actual result: after making an adjustment, the shading disappears in some places and the shading edges that are displayed are not the actual edges, which makes it impossible to make accurate changes in the shading. When a pdf is made, the shading looks how it should look, so no issues there. It is merely when working in Indesign that the display of the shading is faulty. At first, when opening the Indesign file, the shading is displayed correctly, but when a change is made in the (shading of) the area, the shading breaks up, so you can't see what you are actually doing.

Reproduce: make an adjustment in the shaded area. Text in columns, anchored objects in text, placed images, shading merged

Indesign 2025, 20.1