NEW item type, different icon, appears in spreadsheet view, Timeline continues showing "event" icon

Windows 365
created a new item type to serve as event, with a different icon than the diamond of events. Changed type of an event to new type. It continues to have the “event” icon in the timeline. In the spreadsheet and the inspector panel it appears with the new icon.
I want the changed icon in the timeline.
Have seen similar questions, it seems it is not possible to see other icons except the diamond on the timeline?