I am not sure of all the situations where this can come up, but I hit one just now. There's definitely something fishy going on which you can see in the inspector with the configuration error.
This is in 100% normal gameplay, btw. It's simply setting the text from one thing to another. Here's all the info I can really think to include:
info.Count = 75
Submesh_infoIndex = 167
test set to: "<e=excl=open><f=Retron2000Regular>Sooner you say goodbye, sooner you greet Din\' once again!<e=excl=close><e=excl=open> Smartsmart plan!<e=excl=close></f>"
Relevant stack trace (line counts may be slightly off due to some comments I've added while exploring code):
Void SuperTextMesh:UpdateMaskingOnAllSubmeshes () (/Users/draquethompson/Unity/Transience/Assets/Clavian/SuperTextMesh/Scripts/SuperTextMesh.cs:7473)
Void SuperTextMesh:RecalculateMasking () (/Users/draquethompson/Unity/Transience/Assets/Clavian/SuperTextMesh/Scripts/SuperTextMesh.cs:7457)
Material STMMaskableGraphic:GetModifiedMaterial (Material) (/Users/draquethompson/Unity/Transience/Assets/Clavian/SuperTextMesh/Scripts/STMMaskableGraphic.cs:328)
Material STMMaskableGraphic:GetMaterialForRendering (Int32) (/Users/draquethompson/Unity/Transience/Assets/Clavian/SuperTextMesh/Scripts/STMMaskableGraphic.cs:319)
Void STMMaskableGraphic:UpdateMaterial () (/Users/draquethompson/Unity/Transience/Assets/Clavian/SuperTextMesh/Scripts/STMMaskableGraphic.cs:295)
Void STMMaskableGraphic:OnRebuild () (/Users/draquethompson/Unity/Transience/Assets/Clavian/SuperTextMesh/Scripts/STMMaskableGraphic.cs:228)
Void SuperTextMesh:Rebuild (Single, Boolean, Boolean) (/Users/draquethompson/Unity/Transience/Assets/Clavian/SuperTextMesh/Scripts/SuperTextMesh.cs:1652)
Void SuperTextMesh:InternalRebuild (Single, Boolean, Boolean) (/Users/draquethompson/Unity/Transience/Assets/Clavian/SuperTextMesh/Scripts/SuperTextMesh.cs:1530)
Void SuperTextMesh:set_text (String) (/Users/draquethompson/Unity/Transience/Assets/Clavian/SuperTextMesh/Scripts/SuperTextMesh.cs:257)
Void Assets.Scripts.TypeToTextmesh:TypeText () (/Users/draquethompson/Unity/Transience/Assets/Scripts/UI_Scripts/TypeToTextmesh.cs:383)
Void Assets.Scripts.ConversationUI:UpdateConversation () (/Users/draquethompson/Unity/Transience/Assets/Scripts/UI_Scripts/ConversationUI.cs:436)
Void Assets.Scripts.TransConversationState:ConversationUpdated () (/Users/draquethompson/Unity/Transience/Assets/Scripts/TransConversationState.cs:41)
Void Assets.Scripts.TransConversationState:set_CurrentConversation (TransConversationNode) (/Users/draquethompson/Unity/Transience/Assets/Scripts/TransConversationState.cs:18)
Void Assets.Scripts.ConversationUI:EndCall (Boolean) (/Users/draquethompson/Unity/Transience/Assets/Scripts/UI_Scripts/ConversationUI.cs:401)
Void <>c:<AddOnclickFunctions>b__7_4 () (/Users/draquethompson/Unity/Transience/Assets/Scripts/UI_Scripts/UIControls/ConversationVerticalButtonMenu.cs:20)
Void UnityEngine.Events.InvokableCall:Invoke () (Unknown Source:0)
Void UnityEngine.Events.UnityEvent:Invoke () (Unknown Source:0)
Void Assets.Scripts.FaceButton:MainButtonClick () (/Users/draquethompson/Unity/Transience/Assets/Scripts/UI_Scripts/UIControls/FaceButton.cs:51)
Void Assets.Scripts.FaceButton:<Awake>b__23_0 () (/Users/draquethompson/Unity/Transience/Assets/Scripts/UI_Scripts/UIControls/FaceButton.cs:39)
Void UnityEngine.Events.InvokableCall:Invoke () (Unknown Source:0)
Void UnityEngine.Events.UnityEvent:Invoke () (Unknown Source:0)
Void UnityEngine.UI.Button:Press () (/Users/draquethompson/Unity/Transience/Library/PackageCache/com.unity.ugui@1.0.0/Runtime/UI/Core/Button.cs:70)
Void UnityEngine.UI.Button:OnPointerClick (PointerEventData) (/Users/draquethompson/Unity/Transience/Library/PackageCache/com.unity.ugui@1.0.0/Runtime/UI/Core/Button.cs:114)
Void UnityEngine.EventSystems.ExecuteEvents:Execute (IPointerClickHandler, BaseEventData) (/Users/draquethompson/Unity/Transience/Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/ExecuteEvents.cs:57)
Boolean UnityEngine.EventSystems.ExecuteEvents:Execute (GameObject, BaseEventData, EventFunction`1) (/Users/draquethompson/Unity/Transience/Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/ExecuteEvents.cs:272)
Void UnityEngine.InputSystem.UI.InputSystemUIInputModule:ProcessPointerButton (ButtonState, PointerEventData) (/Users/draquethompson/Unity/Transience/Library/PackageCache/com.unity.inputsystem@1.14.0/InputSystem/Plugins/UI/InputSystemUIInputModule.cs:744)
Void UnityEngine.InputSystem.UI.InputSystemUIInputModule:ProcessPointer (PointerModel) (/Users/draquethompson/Unity/Transience/Library/PackageCache/com.unity.inputsystem@1.14.0/InputSystem/Plugins/UI/InputSystemUIInputModule.cs:489)
Void UnityEngine.InputSystem.UI.InputSystemUIInputModule:Process () (/Users/draquethompson/Unity/Transience/Library/PackageCache/com.unity.inputsystem@1.14.0/InputSystem/Plugins/UI/InputSystemUIInputModule.cs:2431)
Void UnityEngine.EventSystems.EventSystem:Update () (/Users/draquethompson/Unity/Transience/Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/EventSystem.cs:530
