wproofreader.js error when updated to Drupal 10.5.1

Problem/Motivation

Updated Drupal to 10.5.0. Part of this update is updating ckeditor to 45.2.0

Somewhere in this update, the wproofreader plugin breaks. On editing pages using ckeditor, the toolbar no longer appears and the following console error can be found:

ckeditor5.js?syjj3r:467 TypeError: this._userOptions.hasOwnProperty is not a function
    at T._setAutoStartup (wproofreader.js?v=20240122:5:12448)
    at T.init (wproofreader.js?v=20240122:5:11786)

Steps to reproduce

Update Drupal to 10.5.0. Enable WProofreader plugin and see that no toolbar appears.