Originally Posted by
adam.smith
Both are 320s, and I don't think it's a range issue, but LAX is experiencing heavy delays due to runway/taxiway construction, according to EF, so perhaps they need to take on more fuel to account for potential holds due to ground delays.
YUL-LAX is 2,481 miles which is pretty close to maximum range for a full A320 going into a headwind. That creates the potential for a tech stop when the stars don't align.
Some combination of full flights (Christmas), risk of incoming delays and strong headwinds is almost certainly the cause.