Here you go. A properly-formatted bug report.
Homecoming: City of Heroes Bug Report
What's the problem?: Captive / Escort / Ally dialogue all plays upon entering a mission regardless of player distance.
Affected Area: Architect Missions
Affected Versions: Retail Issue 14 to now (Homecoming Issue 28, Page 2 - 282.6992)
Details
If the objectives "Free a Captive", "Add an Ally", or "Add an Escort" are utilized, and the captive or surrounding enemies have been given Unaware / Inactive and/or Attack dialogue, then about a second after entering the mission, all Unaware, Inactive, and Attack dialogue will play for all relevant NPCs. This also causes the NPC animations to stop playing. The dialogue(s) will play in the following order: Enemy Unaware -> Captive Inactive -> Enemy Attack -> Captive Attack.
This is a bug that has been in the game since retail and it almost exclusively resides in Architect Missions.
This does not appear to affect any other kind of NPC or object. This "text spam" bug also happens if relevant objectives are activated after the map is loaded. For example, if "Free Captive: Bob" is set to activate only after "Defeat Boss: Sam" is completed, then the NPCs in the "Bob" event will say all of their Unaware / Inactive and Attack dialogue at once.
According to a developer's post on this thread, certain maps which are flagged as being "outside" are considered a "single room". As such, this causes the NPCs to act as though the player is right there in front of them regardless of actual distance. Why this triggers all of their optional dialogue save their "rescued" dialogue is beyond me. It also doesn't seem to be linked to specific maps as all of the maps I tested… indoor, outdoor… small, medium, large… special, et cetera… all suffered the same bug.
I've personally tested the following maps and they all gave the same results: