EXTINT inconsistent timestamp

Q&A forumEXTINT inconsistent timestamp
gedizman asked 3 weeks ago

We have the extint pin and ground connected to a hot shoe trigger and enabled the time message in UCenter. Using Mission Planner to fire the camera we are getting more timestamps than shutter events. It is inconsistent. Although there are doubles that are close together, therefore it is easy to see where two events are present where their should only be one, we would like to know why this is happening (as our flights usually involve 200+ photos I would not want to manually look for near duplicates). 
We have checked the camera settings and the hotshoe itself and used multiple hotshoe connectors – we get occasional near duplicate events each time and frankly we have run out of ideas. I am assuming others have dealt with this problem and thus would welcome any suggestions as to what we do next to try and eliminate this problem.
Thanks in anticipation of your help.