Yes I have. Sorry, my initial comment made it sound like I hadnt.
I was operating on the assumption these are decals because it is a wetlease and I was told on good authority that the first plane in the new livery last fall was actually all decals. But its also possible they just painted the fuselage and not the engines for a wet lease. It a bit different than what they did with recent seasonal 737s though!
The A320's are in fact wrapped with decals, however they are not wet-lease aircraft. They are dry-lease and are operated by Transat pilots and FA's. The reasons the engines weren't wrapped, or so I am told, had to do with approvals from some governing body like Transport Canada or Condor. Not sure who exactly or what exactly didn't allow them to be wrapped though... And to be honest, engine wraps aren't all that common anyways.
Also the first aircraft in the new livery last year, C-GTSN, is not a wrap and is 100% paint. You might be confused as it flew from GIG-YUL with a temporary wrap over-top of the aircraft to not spoil the surprise of the livery reveal. When it got to YUL and set up in the hangar, they peeled the wrap off the night before the reveal.
And finally to touch on the seasonal 737's compared to the A320's, when Transat got its first 737 in 2014 they wrapped it in the full livery. Probably has something to do with publicity, branding etc. Same could probably apply to the A320's. They will also stay a lot longer than any of the winter-seasonal 737's, hence why those aren't wrapped in the full livery. Sunwing does the same thing too, they just slap their tail and titles on the aircraft for a few months, or do an entire fuselage sticker advertising resorts or destinations.