I have had this problem before and got tired of trying to find out why this happens and just made a new part. This is the second time this has happened so it's time to investigate.
The long explanation is I have a customers file which has many holes in it. For the manufacturing purposes I mark all the holes with a point, fill the hole and then add an "etch" sketch attached to that point to indicate to out machine shop the type of hole (M8, M10....) after it leaves the laser table.
The problem is the sketch with all the points on it is not visible even though it's turned on. Changing model or sketch colors doesn't help either.
It's probably something simple that I'm not clicking or something right? I'm tired and it's Sunday, I blame that.