Do you have status (A-list or A-list Preferred)?
Do you have a CC?
Just trying to figure out if your particular case is not due to the fare class purchased but instead due to either status or a CC.
Also we'll need to keep an eye out on the Boarding Group the Companion gets because once assigned seating happens it no longer (at least according to SWA) will be an extended perk like right now you'll get sequential boarding groups, once assigned seating happens it goes more based on what the Companion's situation is or at least that's what SWA says
"For Companion Pass holders and Companions, boarding group will be assigned based on their seat location or Credit Cardmember/Tier boarding benefit, whichever is higher. Companion Pass holders and their Companions will both be eligible for the most favorable seat options conferred by their individual Tier status, Credit Cardmember status, or fare. Sequential boarding is not guaranteed. We’ll share more information about boarding and airport experience as flights with assigned seating start to take off on January 27, 2026."