I've never played any Fallout 3 DLC's, but the dialogue here suggests to me that this isn't supposed to happen. I went to my playerhouse, slept, and when I was going to leave this guy shows up and talks to me, and leaves when I say goodbye.
Here's my load order
[collapsed title=Load Order]
FalloutNV.esm
DeadMoney.esm
HonestHearts.esm
OldWorldBlues.esm
LonesomeRoad.esm
GunRunnersArsenal.esm
CaravanPack.esm
ClassicPack.esm
MercenaryPack.esm
TribalPack.esm
Fallout3.esm
Anchorage.esm
ThePitt.esm
BrokenSteel.esm
PointLookout.esm
Zeta.esm
TaleOfTwoWastelands.esm
TTWFixes.esm
Project Nevada - Core.esm
Project Nevada - Equipment.esm
Project Nevada - Rebalance.esp
Project Nevada - Cyberware.esp
Project Nevada - Extra Options.esm
Project Beauty.esm
New Vegas Redesigned 3.esm
Gomorrah Redesigned.esp
NevadaSkies.esm
streetlights.esm
FreesideOpen.esm
NVStripOpen.esm
oHUD.esm
TTW_XPReduction.esp
TTW_SuperMutantRebalance.esp
TTW_StashPackOptions.esp
TTW_StartupMenu.esp
TTW_SpeechChecks.esp
TTW_OutcastTrading.esp
TTW_NoKarmaDCFollowers.esp
TTW_MoreCookingItems.esp
TTW_Reputation.esp
TTW_Bobbleheads.esp
TTW_AnchorageCustomization.esp
Delay DLC - TTW.esp
Project Nevada - Cyberware Additions.esp
Project Nevada - Rebalance Complete.esp
EVE FNV - ALL DLC.esp
TTW EVE + Project Beauty.esp
Project Nevada - All DLC.esp
Project Nevada - EVE All DLC.esp
Project Nevada - TTW.esp
PNxEO MCMScriptFixes.esp
Improved Ballistics Effects V2.esp
dD - Enhanced Blood Main NV.esp
dD-Smaller Wounds.esp
dD-Smaller Wounds - EVE.esp
dD-Reduced Ragdoll Force.esp
dD-Reduced Dismember Force.esp
dD-Reduced Dismember Force - EVE.esp
dD-Less Screen Blood Time.esp
dD-Smaller Spatters Realistic.esp
Boacombat2glove.esp
boa ncrpahelmet.esp
FCO - GlowingOne.esp
New Vegas Redesigned 3.esp
Jonathan Nash (darker).esp
Usanagi (more Asian).esp
Cass alternate version.esp
Veronica NVR 2 version.esp
The Mod Configuration Menu.esp
The Weapon Mod Menu.esp
FreesideOpenPatch.esp
FSOmusic.esp
outsidebets.esp
athornysituation.esp
awilderwasteland.esp
betsybrahminFSO.esp
StripOpenMain.esp
MusicRecovery.esp
Lucky38Suite_Reloaded.esp
LFox Missing Ammo Recipes GRA DLC.esp
LFox Missing Ammo Recipes HH DLC.esp
LFox Missing Ammo Recipes.esp
wasteland_travel_caravans.esp
ttw_transportalponder.esp
TTW_Difficult_Journey.esp
TTW_Crashed_Vertibird.esp
Brotherhood and House Alliance.esp
FlashlightNVSE.esp
DYNAVISION 3.esp
NevadaSkies - TTW Edition.esp
Mojave Nights.esp
LodFixer.esp
Zan_AutoPurge_SmartAgro_NV.esp
TTW_Companions_Essential.esp
Total active plugins: 94
Total plugins: 99
[/collapsed]
I have the delay DLC plugin enabled, but I'm not sure at all what would cause this to happen :P. To my knowledge I haven't triggered the discovery of any DLC quests in this playthrough.

