Since coming back to work on the 3rd of January, we have been having workflows issues, workflows running slow or completely not starting. All of these issues are occurring on multiple workflows on different lists and there have been no actual updates on our end which would correspond with the issues we are experiencing. Because the slow workflow issues appear to be difficult to specifically define in a manner which is specific enough to pinpoint a resolution, let's focus on the "Not Started" "Initiator Anonymous" issue and hope they are related.
We have a number of workflows which are not starting, when viewing the workflow we get the following status.
This is occurring by both automatically started workflows and manually started workflows by a site collection administrator. This is SharePoint online and the only posts I can find about the issue appear to relate to server issues, which I have no access too.
https://social.technet.microsoft.com/Forums/Windowsserver/en-US/15c22a8c-90e0-43a2-81dd-a999afaa3e0e/workflow-created-using-sharepoint-designer-is-not-getting-started-and-the-initiator-is-anonymous?forum=projectserver2010general
http://www.sharepointpitstop.com/2016/03/workflow-initiator-anonymous-internal.html
https://answers.microsoft.com/en-us/msoffice/forum/msoffice_sharepoint/sharepoint-online-workflows-stuck-at-not-started/1a045f6e-d831-4794-a8d7-a0fb55343cd5
https://answers.microsoft.com/en-us/msoffice/forum/msoffice_sharepoint-mso_winother/sharepoint-online-workflows-stuck-at-not-started/1fafd4fa-9c0b-4b7b-ab7b-e8400f8ea4ed