Containment Bay S1T7 included in Trial Roulette as a new player

Some time ago, I got into Containment Bay S1T7 on Trial Roulette - for the first time. This caught me by surprise because Trial Roulette is only, as far as I know, supposed to take from the pool of trials that you have already done before... and this instance was FOR SURE a trial that I have not done before.

Earlier today I got into the instance again and someone in the party in the same situation I was in before. I'm pretty sure now that it's some sort of bug.

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Following the format (only including relevant information):

Frequency: Once
World name: Cactuar
Character name: Lunie Khit
Party or solo: Solo
Steps:
1. Unlocked quest to undertake Containment Bay S1T7 trial
2. Tick the box for Duty Roulette: Trials and click Join
3. Somehow get into Containment Bay S1T7

It isn't a bug. If you have unlocked a dungeon/ trial but haven't completed it, you can still get it on roulette.

That would be conflicting to what it says in the Duty Roulette: Trial tooltip though.

http://i.imgur.com/g58q6yJ.png

It clearly says there "selected at random from among those you have completed". So while this might not be an issue solely with Containment Bay S1T7 (or maybe it is? I dunno), it's still not working as described.

It seems they forgot to update the description when they changed the way the trial roulette worked. It used to work just like the Expert and "high-level" (now known as level 50) roulettes, but it was changed to work like the "Low-level" (now: Leveling) and Guildhest roulettes with the launch of Heavensward.