Hi Micheal,
I suspect the mobile site might be responsible for the indexed urls issue. Your mobile site has loads of indexed pages with the shorter urls: https://www.google.com/#output=search&sclient=psy-ab&q=site:m.eventective.com&oq=site:m.eventective.com&fp=9861fb8dc6b3e7c
Before the 301 redirects on the mobile site were created, were the rel canonical links pointing to the truncated urls on the main site? Seems to be the case on this random page I grabbed:
So a kind of odd mixture of 301s on the main site, and a well indexed mobile site saying the rel canonical on the main site is the shorter url. Seems maybe the rel canonical won! Are you sure this is a recent issue? Maybe it has been like this for a while and just not noticed much?
I would think that with the 301s and rel canonicals now properly implemented on the mobile site then the index will slowly sort itself out. I suppose you could put a rel canonical on the main site page also referencing itself, might speed up the process a bit more.
Agree with Jesse that it is not likely a major worry and wouldn't think this alone would cause a ranking issue.