In the View Settings of your web part grouping the items of "CounterParty", confirm that the column showing the values "George" and "Robert" (I assume this would be
Title (linked to item with edit menu), not
Title (linked to item) nor plain
Update: Based on the discussion in the comments, I'm strongly suspecting this is a bug in SharePoint.
I've had a slightly similar issue with using Grouped By view (here), and despite reporting it to Microsoft, it hasn't been fixed ever since. The view is generally unstable, and the might be a little to do.
I'm not aware of a fix for problems with Grouped By view, but I also haven't made attempts for a long time. A suggestible step would be to report this issue to Microsoft and hope to get an answer. By using TechNet forums you may or may not get an answer from a Microsoft's employee, and you might also want to try to contact their support directly. Another suggestion, a bit out of the box, would be to try to add your web parts to different web part zones (you might need to change the page's layout to do so). Alternatively you could try to place the web parts horizontally aligned (so side-by-side, as the default layout works vertically). It would be doable as detailed in here: Answer to How to have two web parts side by side in same zone.