There seems to be a little confusion in all this (or maybe just I am easily confused) but it is absolutely valid to put General Business as a heading at an EC meeting since that is the forum for general discussions as well as specific agenda items. Bear in mind that there are limits to decisions that the EC can make without referring matters to a General meeting.
And there would be nothing wrong with having “General Business” as a section heading in an AGM agenda – along with, say, “Finances” and Maintenance” – provided that heading relates to specific motions that are listed in the agenda.
And you could even have a section as part of the AGM where general business was discussed but no decisions were made or votes taken.
Others disagree with this – preferring to keep the AGM “clean” so there is no doubt about what has been discussed and agreed – but I think there are few enough occasions when you can get a lot of owners together to get a sense of how they feel about various issues in the building BEFORE you put items on an agenda.
Where there is a problem is where new items are added and voted on at a General Meeting without owners having prior knowledge through a correctly issued agenda.
In those cases, where an item isn’t on an agenda but later appears in minutes as a resolution, the case for invalidating the decision would be pretty strong.