Hey there, it looks like you've split the Legendary missions over your Titan and Hunter, which has let you complete the triumph - however to qualify for their exotic, an individual character needs to have done all 14 missions. So both your Titan and Hunter are missing Legendary completions from the list, and that's why the exotic is not available. However now the triumph is complete, the exotics can be farmed from the post-campaign 'The Sieve' activity, which may be faster than completing the missed Legendary missions on each. Are you trying to interact with a terminal while within a mission - such as a replay of Commencement? Doing this will reset your Rosetta level down to what it would have been the first time you played it. Meanwhile the Graviton Spike will still hijack a terminal within that mission and apply a Rosetta 3 lock on it, softlocking the mission. But you should be able to approach it while in typical patrol mode, is that not the case? Are you doing it on a character who has earned Rosetta 3? The upgrades are somewhat character specific so the triumph may only be saying one character earned it - a specific character's upgrade level can be checked on the Kepler map, there's a sidebar for upgrades and resources.