HELP!!!! Terrain disappears when changing resolution!!!!

Hi, I really really need help. The terrain disappear when changing the resolution. Look at the pictures. All ok in 19201080, but when changing to 12801024 the terrain disappear. Ok, It not really disappears, because it is there and I can walk on it. It’s like that is transparent after the change. Please, I really need help. Sorry my english.

Please somebody! At least an opinion.

Same problem here.

You can disable/enable your Camera when a resolution change has been detected, this works but its just a quick workaround.