@Andy_P: Are your suggestions a work around or confirmation that Kicad’s behaviour is correct? I would have thought that pcbnew should be entirely real-estate driven to match reality - especially the DRC. (I must admit to similar - but not identical - thoughts in respect of ERC for schematic layout, but realise how naive/heretical that must sound.)
It is unfortunate that the push & shove router in the openGL mode can break traces occasionally. Running the Merge overlapping traces can clear up some of these.
Today after the computer had been to sleep and restarted kicad it showed zero unconnected.
So guess its fixed.
Tried yesterday to restart kicad but it had no effect.
this function worked for me, I had a problem that when performing the DRC check, it shows no error and no details about unconnected pinsd/vias, I checked almost everything on the board but still there was a small information that i had 1 unconnected. using Edit–> Cleanup Tracks and Vias Had deleted the overlapping tracks which you cannot notice easily in your board. I suggest trying it.