Calendar Reading Pane - meeting participants are no longer shown

I used Calendar Reading Pane a lot to check quickly the topic and audience of the meeting. Recently something has changed and Reading Pane no longer shows meeting participants - only organizer. I have to open the meeting and go to Tracking or Schedule Assistant to see participants. This is annoying if you have dozens of meetings per week and much choose between conflicting ones. Is this a new "outlook feature" or something went wrong with my outlook?