What they are is design rule check net completion warnings. That's the easy bit.
Why they've appeared in that pattern I have no idea. It's possible that under [Settings], [Preferences] you've got 'Online DRC' checked on the PCB interaction tab, but that doesn't explain why they all seem to be in the wrong place (unless it would have been the right place if you hadn't moved the design, and they've just got left behind).
Net completion warnings are given where a track isn't fully routed, so if you've still got the yellow rubber bands on your design, you're likely to get these. You can disable the check by unchecking the 'Net Completion' box in the DRC setup screen.