How to distinguish Time-bound vs One time events in a timeline

I'm working on a 'Timeline' component, where there are two kind of events that need to be represented:

  1. Time-bound events: An event that has a fixed start and end time (for example a meeting)
  2. One Time Event: This kind of events happen only once (example: A file has been uploaded, or a request has been approved)

As of now for the 'Time-bound' events I have shown start and end time as dots and connected them with a line, and for the One-time events are represented by single dots.

When we did some usability testing,

Users thought that the single dots are events that are 'yet to Start'

(Even though there were clear info about the event on mouse hover tooltip)

Is there a way to visualize them more clearly?

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