I have got the same issue, when i disable landscape layers the problem dissapears but when i enable them agian same issue.
Edit:
So i figured out that the infinite loading only occurs when i use: sections per component 2x2.
My landscape resolution is 8191x8191, section size 255x255, number of components 32x32.
So when i use sections per component 1x1 the loading finishes after a couple seconds but the editor performance is very bad and simulating in normal editor viewport is 30fps and when i switch to fullscreen its 150fps.