Having the same issue reported by many, but getting an error:

Root level exception in OnGUI(): System.IndexOutOfRangeException: Index was outside the bounds of the array.
[Ref 5233D20E]
at ResearchPowl.NodeUtil.LocalOutNodes (ResearchPowl.Node node) [0x0001d] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00064] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00088] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00088] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00088] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00088] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00088] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00088] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00088] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00088] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00088] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers.DFSConnectiveComponents (ResearchPowl.Node cur, System.Collections.Generic.List`1[T] data, System.Collections.Generic.HashSet`1[T] visited) [0x00088] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.NodeLayers+<SplitConnectiveComponents>d__15.MoveNext () [0x0009a] in <e218313df5f54caea1e989b0db8a235a>:0
at System.Collections.Generic.EnumerableHelpers.ToArray[T] (System.Collections.Generic.IEnumerable`1[T] source, System.Int32& length) [0x00032] in <1f993cbf88314b1baa1e10ca917bdc64>:0
<0x12bb77b5630 + 0x000d2> <unknown method>
at System.Linq.OrderedEnumerable`1+<GetEnumerator>d__3[TElement].MoveNext () [0x0001e] in <1f993cbf88314b1baa1e10ca917bdc64>:0
at System.Collections.Generic.LargeArrayBuilder`1[T].AddRange (System.Collections.Generic.IEnumerable`1[T] items) [0x0003d] in <1f993cbf88314b1baa1e10ca917bdc64>:0
at System.Collections.Generic.SparseArrayBuilder`1[T].AddRange (System.Collections.Generic.IEnumerable`1[T] items) [0x00000] in <1f993cbf88314b1baa1e10ca917bdc64>:0
at System.Collections.Generic.SparseArrayBuilder`1[T].ReserveOrAdd (System.Collections.Generic.IEnumerable`1[T] items) [0x00017] in <1f993cbf88314b1baa1e10ca917bdc64>:0
at System.Linq.Enumerable+SelectManySingleSelectorIterator`2[TSource,TResult].ToArray () [0x00037] in <1f993cbf88314b1baa1e10ca917bdc64>:0
at System.Linq.Enumerable.ToArray[TSource] (System.Collections.Generic.IEnumerable`1[T] source) [0x0001f] in <1f993cbf88314b1baa1e10ca917bdc64>:0
at ResearchPowl.Tree.<InitializeLayout>g__MainAlgorithm|23_2 (System.Collections.Generic.List`1[T] data) [0x00056] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.Tree.InitializeLayout () [0x00026] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.Tree.WaitForInitialization () [0x00010] in <e218313df5f54caea1e989b0db8a235a>:0
at ResearchPowl.MainTabWindow_ResearchTree.PreOpen () [0x00008] in <e218313df5f54caea1e989b0db8a235a>:0
at Verse.WindowStack.Add (Verse.Window window) [0x0001f] in <fcfab19af5d14a608a65ebd77f29482f>:0
at RimWorld.MainTabsRoot.ToggleTab (RimWorld.MainButtonDef newTab, System.Boolean playSound) [0x000a2] in <fcfab19af5d14a608a65ebd77f29482f>:0
- PREFIX Dubwise.DubsMintMenus: Void DubsMintMenus.HarmonyPatches+Patch_MainTabsRoot:Prefix(MainButtonDef& newTab)
at ResearchPowl.MainButtonWorker_ResearchTree.Activate () [0x00027] in <e218313df5f54caea1e989b0db8a235a>:0
at RimWorld.MainButtonWorker.InterfaceTryActivate () [0x0008d] in <fcfab19af5d14a608a65ebd77f29482f>:0
at RimWorld.MainButtonWorker.DoButton (UnityEngine.Rect rect) [0x000ee] in <fcfab19af5d14a608a65ebd77f29482f>:0
at ResearchPowl.MainButtonWorker_ResearchTree.DoButton (UnityEngine.Rect rect) [0x00001] in <e218313df5f54caea1e989b0db8a235a>:0
at RimWorld.MainButtonsRoot.DoButtons () [0x00119] in <fcfab19af5d14a608a65ebd77f29482f>:0
at RimWorld.MainButtonsRoot.MainButtonsOnGUI () [0x0001a] in <fcfab19af5d14a608a65ebd77f29482f>:0
- PREFIX Dubwise.DubsMintMenus: Void DubsMintMenus.HarmonyPatches+Patch_MainButtonsOnGUI:Prefix()
at RimWorld.UIRoot_Play.UIRootOnGUI () [0x0003a] in <fcfab19af5d14a608a65ebd77f29482f>:0
- POSTFIX net.pardeike.rimworld.mod.camera+: Void CameraPlus.UIRoot_Play_UIRootOnGUI_Patch:Postfix()
at Verse.Root.OnGUI () [0x00046] in <fcfab19af5d14a608a65ebd77f29482f>:0
- POSTFIX net.pardeike.rimworld.mod.camera+: Void CameraPlus.Root_OnGUI_Patch:Postfix()
UnityEngine.StackTraceUtility:ExtractStackTrace ()
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:Verse.Log.Error_Patch1 (string)
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:Verse.Root.OnGUI_Patch1 (Verse.Root)