The issue comes down to the interpretation of "domiciled":
The debate over who can and can’t vote in Quebec stems from different interpretations of the domicile rule, which requires all electors to have been domiciled in Quebec for six months.
Stéphane Beaulac, a professor in the faculty of law at the Université de Montréal, explains the domicile rule is based on intention.
“The difference between residing somewhere and being domicile somewhere is that to be domicile, you need to be a resident, but have the intention of making it the centre of your life, of where you live.”
Beaulac said that a person can have more than one residence, but only one domicile. He said it’s up to Quebec revision officers to make that distinction.