disconnected heightmap gives error in microsplat

Thread failed: System.NullReferenceException: Object reference not set to an instance of an object
at Den.Tools.Matrices.MatrixOps.NormalsSet (Den.Tools.Matrices.Matrix src, System.Single pixelSize, System.Single height) [0x00001] in D:\REPOS\AOTA-2021\Assets\MapMagic\Tools\Matrix\MatrixOps.cs:1299
at MapMagic.Nodes.MatrixGenerators.MicroSplatOutput200.Finalize (MapMagic.Products.TileData data, MapMagic.Products.StopToken stop) [0x00170] in D:\REPOS\AOTA-2021\Assets\MapMagic\Compatibility\MicroSplat\MicroSplatOutput.cs:112


simple repro https://cdn.discordapp.com/attachments/445594393848709122/888502285389422602/unknown.png