The new Chapters introduced in Honour the Chapter have unique Solo Mode Abilities as expected, but rather than the now-established (since RoB) Active/Passive descriptors, we instead have "Action" listed for the abilities and no mention of Active or Passive. Are we to assume that "Action: Free" means it's a Passive ability?

I should note that the new Solos for the Black Templars, Storm Wardens, Carcharodons, and Codex Marines do have Active/Passive (and no notation of "Action"). OTOH, the Blood Ravens, Red Scorpions, Flesh Tearers, Raptors, Novamarines, Marines Errant, Howling Griffons, and several others now list an "Action" entry instead of the Active/Passive entry.

The Raptors' solo mode ability, marksman's honour, is passive imo. The attack pattern, clean kill, could be sustained, so you have to pay the cohesion cost only once. The defensive stance, swift withdrawal, is not sustained, i think, so the cohesion cost should be paid every time you want to use it.