Hi oksummer,
I can not reproduce this issue.
I link to http://cutesoft.net/example/general.aspx, clean the editor content and put the html code below into the html view
<a class="active" data-href="/websites/global/products/6pfbnO1KPo8QGElm/img/gallery/gray/gallery-1.png" href="javascript">
<img src="/websites/global/products/6pfbnO1KPo8QGElm/img/gallery/gray/gallery-thumb-1.png" alt=""/>
</a>
Then switch back to normal view and back to html view again, the html code have not been changed. Can you try on the demo page too? Does it get the same problem?
Regards,
Ken