Unable to navigate to user personal pages using: themeDisplay.getUser().getDisplayURL(themeDisplay)

After installing the Microsite Manager plugin the URL generated from the following no longer redirects correctly to the user's personal pages:

<%= themeDisplay.getUser().getDisplayURL(themeDisplay)%>

This was identified after it was found that the Social Office "Profile" plugin stopped working correctly. When clicking on a field a popup appears so that you can edit it. But when clicking to save the change the exception in the attached file occurs and the page reloads to a blank screen with the following URL:

http://localhost:8080/c/my_sites/view?groupId=20435&privateLayout=0
(this is generated from the method call mentioned above)

But it has also been confirmed that using a custom portlet to generate the URL still causes this error to occur.

----

Having searched online for the error string in the exception:

"java.lang.ClassCastException: com.liferay.portal.struts.PortletActionAdapter cannot be cast to com.liferay.portal.struts.ActionAdapter"

I've found the following discussion which may indicate that a portal struts action has been been incorrectly overridden:

https://web.liferay.com/community/forums/-/message_boards/message/13487363

Looking at the source code it looks as though this may be what has happened to the my_sites stuts action:

https://github.com/rivetlogic/liferay-microsite-manager/blob/f097da5e8b21743f15644aa383c70582f7923cae/portlets/micro-site-portlet/docroot/WEB-INF/liferay-hook.xml

I hope this helps. Please let me know if you require any further information.