Hello! 

We noticed, that personalize stop working in TinyMce. I think it can related with update TinyMce library to 7.* version (Optimizely package 5.*).

Case:

1. Input any text
2. Select content
3. Personalize by exist audience
4. Publish page

Our source code before publish:

<div
  contenteditable="false"
  class="epi_pc"
  data-groups="f798953a-c4dc-4cf7-a589-06156b40b8fd"
>
  <div class="epi_pc_h">
    <div class="epi_vg">Test-test</div>
  </div>
  <section contenteditable="true" class="epi_pc_content">
    <p class="body-default">test</p>
  </section>
</div>

Our source code after publish: removed all html code before publish related with audience.

I tested remove attributes in parent div and it happened when we have 

 class="epi_pc"

I also tried to remove all pottential related with it things and use default TinyMce configuration, but have the same issue. We also have legacy project on Optimizely TinyMce package (4.*) and it worked.

Also tried to override settings like: extended_valid_elements, valid_children, valid_elements and other and it helps only part of html code, but attribute «class» removed any way.