Something is definitely skewed in the story telling, or quite possibly the originator of the message is on a completely different frequency that nobody else gets
Far as I know, the only airborne related thing that happened with Canadian M777 during the Afghanistan "era", occurred in 2006, but it did not involve any actual air drops in theatre. Not intentional drops anyway
In the summer of 2006, roughly 6 months after the M777 came into service, the Artillery School SMIG was sent to the states to observe air mobility trials with the M777*. The trials focused on lifting the gun in air mobile Ops (i.e. by helicopter and Osprey), and only limited air borne trials were done. The SMIG did not take part in any of the jumps, and neither did any other Canadian gunners. The intent was for him to quickly get these proper rigging procedures for heli Ops sent overseas, so they could be used instead of the "make shift" techniques the troops had come up with.
The gun had come into service so quickly, the specifics of how to rig the gun had not been worked out yet before it was operationally deployed. It didn't help either that the different nations with aircraft capable of lifting the gun (Dutch, UK and US Chinooks) each had a slightly different twist, so to speak, on the rigging (brakes on/off, number of free chain links, spades up/down). On two occasions guns were damaged as result of the "experimentation" that was unavoidably going on. For the most part it got sorted by Winter 06/07, and the different techniques were passed on from roto to roto mostly as a lessons learned type of thing. It would not be until Winter 2009 that a consensus was reached amongst the different nations lifting the gun, in theatre, on one rigging procedure. By the time CFLAWC finally issued their version of rigging, the gun configuration changed yet again; modifications that required yet more trials. These changes were comm's eqpt hung on the gun carriage itself, which amongst other things changed the gun's C of G.
I've haven't had any direct involvement with the gun in about 2 years now, but still stay in touch with those that are. There is still air mobile training going on with the M777, and there is a Bty developing airborne skill sets, but no air drops with the M777, yet. It might seem makeshift while it is going on, but there is some method to the madness.
* There were only two of us in the school with the background necessary to attend the air mobility trials in the states in 2006, and "bone" was the lucky one that got to go while I, as the School Mr Gnr, worked on 155 ammunition (Excalibur) issues