If the editor's HTML markup contains inline CSS styles, and a CSS attribute value includes a semicolon (;), it breaks the applied styles and throws an exception.
For example:
<p style= "" ....background-image: url('data:image/png;base64...;""</p>
The exception is:
Uncaught TypeError: Cannot read properties of undefined (reading 'trim')
=== ADMIN EDIT ===
The issue can also occur when there is an invalid inline style with two semicolons without a complete style-value pair in-between.
For example:
<p style=""color:red; b ;"">sdf</p>