I’m A List Preferred and booked myself an extra legroom seat. When I went to add my Companion, the app tried to charge a fee to select the extra legroom seat next to me.
I always thought Companions could sit together regardless of seat type, so this threw me off. Turns out it seems to be an app bug. When I tried adding the Companion on a desktop browser, I was able to select the extra legroom seat with no extra charge.
My guess is the app is applying cardholder seat rules instead of Companion logic. If anyone runs into this, try doing it on a browser instead of the app.
Hopefully Southwest fixes this soon.