While quickly turning in the Rock, Paper, Genocide missions, Marcus said something weird in an echo recording like voice. Instead of giving his normal instructions on Corrosive weapons, he said:
“Hello Scooter. Since you are a freeloading piece of crap, I sold your stuff to the black market.”
Even though Subtitles were on, those words did not appear.
Here is a highlight of the video with the strange lines starting at about 45 seconds.