Location: Gyr Abania, The Lochs, Ala Mhigan District, X:34.0 Y:32.0 Z:0.7
Quest progress: The Resonant (MSQ), final step: "Speak with Alphinaud."

The background NPCs that have this chat bubble typo seem to appear at any time after accessing the Ala Mhigan District during/after the MSQ "The Resonant", but the NPCs then disappear after completing the MSQ "Stormblood".

Specifically, one of the two NPCs at this location says "Don't even need" which is a typo. It's not clear what he was originally supposed to say, since the sentence is cut short.