Edit: One of the wolves was on Flea Market (forgot they can't fight in Campaign while in the flea market), however I thought a warning message used to pop up when trying to put unavailable wolves on your team. So this might still be a glitch?
After pressing the "Save party" button in the the campaign, the party members tab ended up vanishing and once the page was refreshed it reverted back to my original team.
I use a MacBook and was playing on Safari.
