Why is another part of the object displayed when rendering?

Question

Blender

Answer 1

Most likely the problem is that you have created 2 objects and one of them is hidden.
In the settings of each object, you can hide the object both in the viewport workspace itself during operation and during rendering.
Here, apparently, you have it hidden for the viewport, but not for rendering.
For example, a person works with a complex scene where there are a lot of objects, he can work with them in turn and hide them so that already worked objects do not load the system once again when working. But during rendering, they should all be displayed .. for this, they made this opportunity to separately set the display settings for different operating modes.