I’M having the same problem ,but in 4.19.2, with a old terrain still evolving. I know this is slightly old, but approrpiate nonetheless,unless I should post new, fine just let me know.
So far its just a few areas, plus one area where terrain is not visible and player falls through there too.
I also notice, not all ‘tiles’ of terrain( components) are the same color, and sometimes as I sculpt, a ‘opening’ in terrain occurs at intersecting points.
PLs see images, would LOVE to know whats going on…this is a dev-stopper ,if I can’t rely on terrain I can’t plan changes and be assured of success.
ty for any help on this.