Hi @info97662
I see that you are using VH unit of measure.
Due to some limitations Editor X Preview sometimes fails to show the real picture when we use VH.
As the temporary workaround I recommend using Viewport Resize r (Google Chrome extension that helps to preview live sites) . It is helpful when you are using VH for section height.
Preview your site by using this tool. It should show you the issues you need to fix.
Furthermore, in order to take advantage of VH you need to use it in combination with other tools like text scaling for example.
Lastly, if u see that mobile breakpoint got messed up use remove overrides button. It resets the design or layout properties of an element back to the properties of the largest breakpoint. I hope it will help you find the section that disappeared.
If the issue still persists contact customer care here .
Have a good one !