NRE when validating without Terrain Tools

[Insprill]

NullReferenceException: Object reference not set to an instance of an object
MapifyEditor.Export.Validators.TerrainSceneValidator+<>c.<Validate>b__0_1 (UnityEngine.Component comp) (at <6c995e8150fa4940ac631d120153741d>:0)
System.Linq.Enumerable+WhereArrayIterator`1[TSource].ToArray () (at <351e49e2a5bf4fd6beabb458ce2255f3>:0)
System.Linq.Enumerable.ToArray[TSource] (System.Collections.Generic.IEnumerable`1[T] source) (at <351e49e2a5bf4fd6beabb458ce2255f3>:0)
MapifyEditor.Export.Validators.TerrainSceneValidator+<Validate>d__0.MoveNext () (at <6c995e8150fa4940ac631d120153741d>:0)
Mapify.Editor.Utils.Extensions.ToList[T] (System.Collections.Generic.IEnumerator`1[T] e) (at <6c995e8150fa4940ac631d120153741d>:0)
Mapify.Editor.Validators.Validator+<Validate>d__3.MoveNext () (at <6c995e8150fa4940ac631d120153741d>:0)
UnityEngine.Debug:LogException(Exception)
Mapify.Editor.Validators.<Validate>d__3:MoveNext()
Mapify.Editor.Utils.Extensions:ToList(IEnumerator`1)
Mapify.Editor.MapValidationGui:OpenAndValidate()
Mapify.Editor.MapValidationGui:OpenAndValidate(MenuCommand)

[t0stiman]

What is the desired behaviour when Terrain Tools isn't installed?

a. A message telling the user to install Terrain Tools
b. To skip this validation without error
c. Something else?

[Insprill]

It should work as normal without it installed. It's only a recommendation, not a requirement.