Hi guys, I'm having the same issues as well. Three in fact including this one...which are all fairly new ever since I installed the updates, I bought the Mass Effect Trilogy I beat all 3 games in my first play through with no bugs on 360, no problems at all there were no bugs everything seem to work properly. I played the Trilogy on Xbox 360 first then I bought the PC version Trilogy hoping maybe it wouldn't have these new bugs unfortunately I was wrong it had the same ones 
So....here's the story I decided to replay them all again last year on my 360 version while my nephew watched, it worked all in well for awhile beat the first game made it to the second, after awhile I noticed the Grunt mission glitch up, just for the record I used no mods or Gibbed Save editor at all so my saves were all clean. Wrex told me to talk to the Shaman, even with Wreav instead of Wrex it did this....it wouldn't work the screen would go dark but I could still hear sfx and move my guy at least I heard footsteps of me in the same room still then if I'd reload oddly enough I'd be back in front of the shaman even if I didn't save it there or were close to him...it'd show me talking to the shaman, but then after speaking to him the screen would go dark again. So I couldn't complete that quest. very aggravating
Then this Tali glitch happened during her mission, once I arrived to the scorching hot planet I beat everything, blew the rock up, went to the locker room where the weapons are talked to her on the intercom, then I go down the ramp to the door, see the drones fly by I killed them all then the Geth. On the far side of the room no panel on the door at all. I thought I was the only one with this issue.... now I know I killed them all, it appears several others have this bug. I cannot get to the door there is simply no panel on it at all! I know there was on my first playthrough a few years back before the updates I know it worked you don't forget a game this memorable like the Mass Effect Series. I played it for I can't even count how many hours for the life of me and found nothing no way to get it to open or even appear. No signs of enemies at all it's clearly a bug, even still the door should at least have a red panel on it, it has NONE! Heheh.... 
Glitch bug 3, to top this off I also discovered another new one. When doing Jack's Loyalty mission it automatically makes you leave when she tells you she wants to take a look around even if you permit her to and say okay Jack we'll look around, it cuts you off and immediatly shows you flying off detonating the bomb... it didn't used to do this either because I remember her telling me all about the facility, about her childhood, her room. Very annoying. Now all 3 of these bugs are fairly new, I had no mods, no hacks, no gibbed...nothing just clean saves. In every one of my playthroughs it did this on Xbox 360 and PC Versions of Mass effect 2 from the Trilogy. I wonder if the Updates may have corrupted my save files or something. Any new save I make will do this. All 3 bugs are inevitable there may be more but these 3 are so annoying I can't play ME2 the way I used to.... I fell in love with the game before, now it's partially broken because of these bugs it cannot be completed.
Please Bioware fix this. Because of these glitches we cannot play our great games you made for us properly the way you intended for us to. Something broke Mass Effect 2 for many players. Maybe an update or updates or something else I can't say. I don't see how it can be origin because my 360 game does it too. 
Please Bioware or whoever is in charge of updates, please make an update to resolve these issues and get things back on track the way they were before if you can, for your fans.
Thanks for reading
Sincerely ~Simdrew1993