it's not only the red point it's the orange strike through as well.
What's your exact version of InDesign?
Did you create that document?
Maybe this is a "remnant" of a 3rd-party plug-in for tracking changes, visualizing "deleted text" or "text to delete" in this case?
Never worked with InDesign's own Track Changes features; it seems that track changes with this is only visible in the Story Editor Window. Maybe this is from a plug-in that makes track changes visible in the layout window?