A mistake is always possible.
But are we sure the limitation is strictly for
runway width - or whether, having landed, maneuvering may be problematic? I note a VA 747 that diverted to CYFB in 1996 hit a ramp fuel pump with one engine.
Lot of new construction there 2014-2017 (A380 test was 2006, looks like 747-8 must have been about 2011?) - the gate areas for the new terminal (if actually full of aircraft) don't leave a lot of width for the taxiway.
Churchill is different, with a decent "loop" for getting turned around at the end of RWY 15, but on-the-ramp car parking and other oddities on the main ramp.
Could it also be a tempo restriction due to ongoing construction?
Anyway, some actual aerial views. See any problem areas for big spans?
https://www.google.com/maps/place/Iq...!4d-68.5444448
https://www.google.com/maps/place/Ch...!4d-94.0752232