[2020] Custom made map crash. End Desirable Error. Vehicle Tag Mismatch

Are you using any mods? A lot of mods are made only to run in the simulation (where you build your city) and not in the editors. A mod that isn't meant for the editor could explain why your custom map ends up broken. I recommend disabling any mods you don't absolutely need in the editor to make your map. If you don't need any mods, then using the -disableMods launch option is an easy way to do that.