It's intended and written in the patch notes.. You can only gain exp from high roulette from those dungeons
[3.0] Players will now be rewarded experience points upon completing Duty Roulette: Main Scenario, Duty Roulette: Trials, or Duty Roulette: High Level prior to level 60.
However, players who do not use duty roulette to join level 50 duties associated with the above roulettes will not receive experience points.