How to reproduce:
1. Create UI -> InputField
2. Select InputField in Hierarchy and Change Content Type to Standart, Name, etc... in Inspector Window
3. Change Character Limit to 9
4. Enter Play Mode
5. Write any text into InputField in Game Window
6. While in Play Mode, Select InputField in Hierarchy
7. Under Text field, select whole written text and write anything else

Actual result: ArgumentOutOfRangeException: Argument is out of range.
Parameter name: index
System.Collections.Generic.List`1[UnityEngine.UICharInfo].get_Item (Int32 index) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Collections.Generic/Dictionary.cs:225)
UnityEngine.UI.InputField.SetDrawRangeToContainCaretPosition (Int32 caretPos) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/InputField.cs:1826)
UnityEngine.UI.InputField.UpdateLabel () (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/InputField.cs:1694)
UnityEngine.UI.InputField.OnValidate () (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/InputField.cs:547)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

Reproduced with: 2017.1.4f1, 2017.2.3f1, 2017.4.4f1, 2018.1.2f1, 2018.2.0b5