If this is isolated to this single document, export it to .idml, open that and save as a new .indd and see if the problem is fixed.
If it happens in a new file as well, see Reset InDesign Preferences and Other Troubleshooting and reset the prefs.
Just to check. Can you highlight the text with the text tool, then open the Paragraph tool bar at the top of your screen and share a screenshot?
HI Everybody, I don't know what was going on but I opted for deleting the style and creating a new one that I applied to all the lists, it was a very strange thing though...
That sounds like the sort of minor corruption that usually gets fixed by a trip through .idml. It certainly won't harm your file, and may well save you from other problems, if you go ahead and do that now.