Elinchrom Skyport problem on Canon cameras?

Hi all, I conduct photography workshops where I allow the attendees the use of my Elinchrom Skyport triggers to trigger my studio setup. I have had a few occurences where the Skyport (both models) switch modes from standard to high speed sync randomly when used on Canon cameras. This happened mostly on 7D models but has also occured on a 5D Mk II. I have not seen this problem on any other make of camera. I would like to hear from users here if you have found a similar problem.