Not sure if this is the correct place to report bugs. I have encountered this problem twice, the GND connection not correctly connected but the DRC does not report it. Please see the attached photo. One photo shows unconnected net correctly checked, and second photo shows unconnected GND ball not correcly checked.
I am using version 5.1.6, I also had this problem on different board using version 5.0.1.
At least in theory the ratsnest lines and the DRC report should show the same unconnected items. AFAIK the ratsest lines have sometimes in history been less reliable. In any case the lines are only visual and may easily go undetected in inspection, so the DRC check is authoritative. If some unconnected item isn’t detected by the DRC it’s a very serious bug, potentially leading to big financial loss.
It must be repeatable, so in this case you have to attach an example file unless you can give step to step instructions how to create it from scratch. If you are allowed to attach the file or create a new one with the same problem, you could give it us here as well, so we could check if there’s something else going on.
I am doing another layout now and surprisingly I am finding another GNDREF that is left floating but DRC does not detect it as unconneted while other unconnected GNDREF pins are detected as unconnected. I am too lazy to take a picture but just let you know that KiCad has serious problem in detecting unconnected GND connection.
I will post my files and let you guys know where to get them. Will do it in a day or two.
Indeed. local labels on a sub sheet is another way in which things like these can happen.
No, please do not do this yet.
There are different ways in which this may appear to be a bug, but actually is not.
What is your experience level with KiCad?
A PCB with such BGA’s is likely to be divided over multiple schematic sheets, and incorrect use of local / global and hierarchical labels is for example also a good possibility.
In my opinion it is a good idea to try to make the workload for the developers lower, by first verifying possible bugs are actually bugs before reporting on gitlab.