Am I right in thinking if we did the Mera mission last year, we don't get to do it again? The mission isn't showing up in my journal (or that of my leaguemates), and when I go to Mera's location in Gotham, I can't speak with her. Just curious.
If your toon doesn't have the mission ready in the journal, that means they have already done this one-off mission and you'll have to earn the collection through other means.
Catastrophic Repercussions is correct. It's a one time only mission. You can get the collection pieces from regular collection nodes in Gotham City (and possibly Metropolis too?) though, if that's what you're looking for.
I've been seeing last year's collection items drop in open world, and I already have that set, so I just won't worry about it. Thanks!