I saw this most June/July Saturdays this summer. I see four nonstop flights on AC.com (which is already strange):
AC331 0740-1010 on an A320
AC335 0930-1205 on an A320
AC363 1855-
2230 on an E190 -- I'd hate to be on this one given that...
AC333 1910-
2145 on an A319
Curiously, Google Flights has only 3 flights at those times (331, 335, 333) when searching YUL-YEG, but 335 shows up as 1855-2125 when searching INTL-YEG (though not on AC.com). I'm guessing it's a schedule change that hasn't fully propagated through the system/GDS, but is 333 or 363(/335) going to get the axe?