All the other NPC comlink missions from Kora and all others by Hahn except this one are unlocked.

Kora's, all unlocked after completion:
1-1 First Contact
2-1 Welcome
3-1 A Prestigious Opportunity
3-2 Pioneers
4-1 A New Chapter
5-2 Another Trace
6-1 An Explosive Plot
6-2 Target Acquired

Hahn's, Unlocked after completion:
4-2 Pierce of Cake
4-3 Elemental My Dear

Hahn's, Locked after completion:
5-1 The Shadow Knows

Doesn't make any sense to lock just that one. Lock them all after completion or lock none.