An EC meeting is not the same as a meeting of the Owners Corporation. A meeting of the OC is a general meeting, and certain requirements are applicable to that. An EC meeting is a meeting of the members of the EC. The EC makes decisions on behalf of the OC, with certain decisions being reserved to the OC in a general meeting.
EC meetings can be held either in person or by paper and/or electronically, i.e. by email. An OC meeting cannot be held by paper or electronically, although you can have a “dummy” OC meeting where everyone sends in proxies.
What you have here is a failure of the notice requirements. The issue then is whether the decision would have been any different had the notice requirements been met. The primary people who may have cause for complaint are the EC members, although other owners do have the right to give notice that they object to a certain decision of the EC being made. If that is not the case, then at the most it is a procedural irregularity and in any event as Jimmy points out, all the EC has to do is have another meeting and ratify the decision/s.