[Solved] Weird thing happens during my building for lighting.

[Gerald_Mei (Nathon Mei)]

@NasteX

This looks like low lightmap resolution, also are you sure that your lights are static/stationary?

Post a screenshot of the alt+0 visual mode, if it doesnt work, go to the Lit button (inside the viewport, to the right side of Perspective) > Optimization viewmodes > Lightmap Density and take a screenshot.

After hit Alt+0, I immediately realize it is indeed a resolution problem when I saw all the screen turns into deep dark blue.
Amazing. So I tweaked the resolution until it seems like a little green.
It works as normal now.

Thank you very much.