I don’t think this is a bug, the issue is that the ptToDiamond doesn’t have enough input grids. You need to provide at least two rows of girds in both the U and V directios.
I don’t see any licensing information for you, so I’m not sure which Rhino you are running. Assuming you are looking for “PanelingTools”, you should be able to install the plug-in through the PackageManager.
-wim