It does that because the polygons are limited to the edge of the map and the bevel acts on that accordingly. Use the Edit node tool to move those nodes quite a long way outside the map border. Then the bevel will vanish properly beyond the edge of the map along with it.

But I'll let you into a secret. The real techs are here. I always seem to be telling people to come to the forum because I can't solve the problem myself on FB.

I'm not sure where you have got that impression from, but we don't provide community content on FB.

All content is accessed either through this forum, or via the Profantasy webpage.

Oh Remy's video is just as good, but you would have found my timestamp a bit confusing ;)

You're welcome :)

Night effects cover the entire area, so they reappear beyond the screen. However, when you save your map as a bitmap export (Save as... in the File menu) you will only be rendering the area of your drawing, so you won't see any of that.