Repeating romance dialouge with Garrus in ME2

I think what you are hitting is not a bug, it's the way it worked in the original too, you can go talk to him multiple times and you get the same conversation about preparing for a dangerous mission that talks about flexibility and reach. I can check this later (working on a playthrough where I romance no one in ME2), once I get the no romance save imported into 3, I want my Kaidan butt shot...I am going to go back and see if I can get a romance in 2 to get the achievement. I would suspect the conversation stops once you head to the Collector ship. Has your crew been grabbed yet. If I remember right, once that happens you can go talk to everyone and that ended the repeating conversation with Garrus for me (update - next step is Suicide Mission and the conversation has not gone away non-romance). I will try and see what happens with a romance