Timeline view in Jira spaces has changed over the weekend?

The Timeline view in Jira projects used to show Epics, which you could expand to see all stories within those epics.
Since today it seems that this has changed:

• it's also showing all stories that aren't assigned to any epic
• but more importantly: It's also showing my initiatives and themes that we are using in our Jira plans.
  • What this means is that I can't sort epics anymore independently from the initiatives they have been assigned to
  • When hiding the initiatives and themes via quick filter, only stories are shown (without the epic hierarchy) and with this new icon:
    

Question: how can I get it back to how it was before?