The the worldgen would crash with Worldgen previewer and it crashed once without worldgen previewer.

Logs:
System.IndexOutOfRangeException: Index was outside the bounds of the array.
at Terraria.WorldGen.<>c.<AddGenPasses>b__288_47(GenerationProgress <p0>, GameConfiguration <p1>) in tModLoader\Terraria\WorldGen.cs:line 9476
at WorldGenPreviewer.WorldGenPreviewerModSystem.On_WorldGenerator_GenerateWorld(orig_GenerateWorld orig, WorldGenerator self, GenerationProgress progress) in WorldGenPreviewerModSystem.cs:line 123
at Hook<System.Void WorldGenPreviewer.WorldGenPreviewerModSystem::On_WorldGenerator_GenerateWorld(Terraria.WorldBuilding.On_WorldGenerator+orig_GenerateWorld,Terraria.WorldBuilding.WorldGenerator,Terraria.WorldBuilding.GenerationProgress)>(WorldGenerator , GenerationProgress )
at SyncProxy<System.Void Terraria.WorldBuilding.WorldGenerator:GenerateWorld(Terraria.WorldBuilding.GenerationProgress)>(WorldGenerator , GenerationProgress )
at Terraria.WorldGen.GenerateWorld_RunTasksAndFinish(Int32 seed, Stopwatch generationStopwatch, GenerationProgress customProgressObject) in tModLoader\Terraria\WorldGen.cs:line 14056
at Terraria.WorldGen.GenerateWorld(Int32 seed, GenerationProgress customProgressObject) in tModLoader\Terraria\WorldGen.cs:line 6267
at DMD<DMD<>?9892485::Terraria.WorldGen::do_worldGenCallBack>(Object threadContext)
at SyncProxy<System.Void Terraria.WorldGen:do_worldGenCallBack(System.Object)>(Object )
at Terraria.WorldGen.worldGenCallback(Object threadContext) in tModLoader\Terraria\WorldGen.cs:line 2497
at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart()

[22:10:32.693] [.NET TP Worker/ERROR] [tML]: A problem was encountered during world generation
Jungle Chests
System.IndexOutOfRangeException: Index was outside the bounds of the array.
at Terraria.WorldGen.<>c.<AddGenPasses>b__288_47(GenerationProgress <p0>, GameConfiguration <p1>) in tModLoader\Terraria\WorldGen.cs:line 9476
at WorldGenPreviewer.WorldGenPreviewerModSystem.On_WorldGenerator_GenerateWorld(orig_GenerateWorld orig, WorldGenerator self, GenerationProgress progress) in WorldGenPreviewerModSystem.cs:line 123
[22:10:32.693] [.NET TP Worker/ERROR] [tML]: A problem was encountered during world generation
System.IndexOutOfRangeException: Index was outside the bounds of the array.
at Terraria.WorldGen.<>c.<AddGenPasses>b__288_47(GenerationProgress <p0>, GameConfiguration <p1>) in tModLoader\Terraria\WorldGen.cs:line 9476
at WorldGenPreviewer.WorldGenPreviewerModSystem.On_WorldGenerator_GenerateWorld(orig_GenerateWorld orig, WorldGenerator self, GenerationProgress progress) in WorldGenPreviewerModSystem.cs:line 123
at Hook<System.Void WorldGenPreviewer.WorldGenPreviewerModSystem::On_WorldGenerator_GenerateWorld(Terraria.WorldBuilding.On_WorldGenerator+orig_GenerateWorld,Terraria.WorldBuilding.WorldGenerator,Terraria.WorldBuilding.GenerationProgress)>(WorldGenerator , GenerationProgress )
at SyncProxy<System.Void Terraria.WorldBuilding.WorldGenerator:GenerateWorld(Terraria.WorldBuilding.GenerationProgress)>(WorldGenerator , GenerationProgress )
at Terraria.WorldGen.GenerateWorld_RunTasksAndFinish(Int32 seed, Stopwatch generationStopwatch, GenerationProgress customProgressObject) in tModLoader\Terraria\WorldGen.cs:line 14056
at Terraria.WorldGen.GenerateWorld(Int32 seed, GenerationProgress customProgressObject) in tModLoader\Terraria\WorldGen.cs:line 6267
at DMD<DMD<>?9892485::Terraria.WorldGen::do_worldGenCallBack>(Object threadContext)
at SyncProxy<System.Void Terraria.WorldGen:do_worldGenCallBack(System.Object)>(Object )
at Terraria.WorldGen.worldGenCallback(Object threadContext) in tModLoader\Terraria\WorldGen.cs:line 2497
[22:10:38.803] [Main Thread/DEBUG] [tML]: Process.Start (UseShellExecute = True): "tModLoader-Logs"