Not for me. The reason those tiefling refugees are traveling is directly connected to the prequel tabletop adventure, which also takes place in Avernus. There is a connection there, so I don’t find that thematically odd.
And I’m pretty sure that the forces you face on the ship are cambions. A cambion has an infernal parent while a tiefling has a more distant infernal ancestor.
Ohhhh. cool, and thanks I'm totally going to buy a copy of the prequel.
Also having done the intro about 8 times so far, can confirm that the "backup" to the entity attacking the mind flayer pilots are listed as Cambions.