C'est un sale bug dû à OA.
http://fallout.wikia.com/wiki/You_Gotta_Shoot_%27Em_in_the_Head#Bugs
"If you have completed Operation: Anchorage, and continue until the Waters of Life quest, upon exiting Tranquility Lane, you may be informed that you completed "You Gotta Shoot 'em In the Head""
"If you have already accepted Crowley's mission, installing Operation: Anchorage! during this mission as an add-on will show this mission as complete without any indication of it's completion, and can still be done with full rewards from it."
Tactac > Grave ils n'ont rien à voir et pourtant ils merdent entre eux.