Load LAN game - Old Terrain no longer works

I played a LAN game with a friend using the old terrain option. After we wanted to continue playing the next day, we noticed that the old textures were no longer visible in the game (cliffs old texture/terrain new textures), even though we had still chosen the old terrain option. In case this bug is not yet well known, I would like to mention it. (And loading LAN games is also extremely complicated until it works for us)