Question TmpText not showing under mask after changing show values of tmp shader

original title: Some of the ui material change to "stencil id:1, op:keep, Comp:Equal"
usually they were "Defalut UI Material (Material)"
they are Images with no material.
The problem is tmpTexts under these Images can't be seen.
I tried :
remove the Image, and add component image ,text can be seen
but it change to "stencil id:1, op:keep, Comp:Equal" while on play , then text can't be seen


befored all these happened:
I was using ctrl+z , then got the error below. Switched another scene then found this problem.
error:
InvalidOperationException: Sequence contains no elements
System.Linq.Enumerable.Last[TSource] (System.Collections.Generic.IEnumerable`1[T] source) (at <a6e6599e603241b58034b5ba39fef2ac>:0)
UnityEditor.Graphs.AnimatorControllerTool.UpdateStateMachineSelection () (at <1d4681f7b1d74362928faef31b1df1aa>:0)
UnityEditor.Graphs.AnimatorControllerTool.RebuildGraph (System.Boolean updateSelection) (at <1d4681f7b1d74362928faef31b1df1aa>:0)
UnityEditor.Graphs.AnimatorControllerTool.UndoRedoPerformed () (at <1d4681f7b1d74362928faef31b1df1aa>:0)
UnityEditor.Undo.Internal_CallUndoRedoPerformed () (at <b1863331a9da4cebb6cd21df9a943f93>:0)
UnityEditor.EditorApplication:Internal_CallGlobalEventHandler() (at ?)


edit:
It seems it is control by mask component.
Maybe I changed some value of the textmeshpro shader, then caused text not showing under mask.
still want help : how to reset textmeshpro shader? I forgot which value I changed.

edit:
I use my backup font asset to replace the current one, things are now alright.
Main problem solved
still want to know which value of tmptext (shader or font asset?) changed will cause this issue: text not showing under mask.

 

Has there been any progress on this issue? I'm experiencing this in Unity 2021.3.12f1. My Text Mesh Pro Text asset does not display when it's a child of a scrollview and the mask is enabled, but it does display when the mask is disabled. I need to have both the mask enabled and the text visible.