Bioware has posted some clarification on the lost legendary player status bug.
Lost legendary player status | 03.11.2016, 03:25 PM
We have seen quite a few reports of players who have lost their Legendary Status following Game Update 4.2 on Tuesday. First, a reminder of what Legendary Status is. This system was put in with Knights of the Fallen Empire as a reward for players who had completed all 8 Class Stories all the way through Act 3. We wanted to make sure that their efforts were rewarded, beyond just Achievements alone.
Along with the KotFE launch, we also introduced Start at 60 tokens. Unfortunately, there was a bug where sometimes a character made from a token would grant a completion for Legendary Status. This was not intended as that character never played through and completed Act 3. With Game Update 4.2, we corrected that bug and along with it, removed any unintended progress from Legendary Status. At this time there are a few specific issues that have been raised:
I have a <insert class> that has completed their Class Story but do not have Legendary Status Credit
I completed my Class Story with <insert class> but have since deleted that Character
Players who have completed all eight original Class storylines (by reaching level 50 and finishing their final Class Mission) are considered Legendary and are now identified as such in-game.
You can track your progress towards this achievement on the Character Select screen, where the Class icons on the left light up for completed Class storylines. This panel becomes Gold as soon as you've attained Legendary status. If you're logged into the game, you can track your progress through the Legacy panel (press Y) under Global Unlocks.
Legendary status also grants you a Presence bonus, the full complement of Heroic Moment legacy abilities, and a special icon beside your character name in-game, so that everyone can see your achievement.
NOTE: Outlander characters (starting at level 60 or 65) do not count towards Legendary status since they have no access to the original Class storylines.