Undo Redo doesn't work on paragraph with children.

Hello!

I have this object for the initial editor value, given from the official slate example:

initialValue = [
{
      type: 'paragraph',
      children: [
          { text: 'This is editable ' },
          { text: 'rich', bold: true },
          { text: ' text, ' },
          { text: 'much', bold: true, italic: true },
          { text: ' better than a ' },
          { text: '<textarea>' },
          { text: '!' }
      ]
  }
]

When I mark in the editor for example "text, much" and remove it, then press ctrl+z and after it ctrl+y multiple times, more text gets removed then I initially removed ("text, much").

Thank you for possible solutions!

No source files or tests are named. Reproduce the issue with the supplied initialValue by deleting “text, much,” then using Ctrl+Z and Ctrl+Y repeatedly; inspect the editor’s undo/redo behavior and consider the work done when repeated cycles restore and remove only the original selection.