One glaring mismatch is in the first scene his says "on my own", in the later scene he says "by myself".
This has been fixed on the DVD release. The second flashback is the same scene as the first.

lets kill the editor
Mornings and mirrors only serve to terrify old men.

The point is not that it keeps people from enjoying the film, stuff like this (and most "goofs", actually) doesn't really both me in the slightest. Some people just enjoy picking up on goofs & movie trivia, that's all.

Glaring? I consider the sound guy crashing through the wall into the lead actor a glaring mistake. This shouldn't keep anyone from enjoying the film.
I agree with someone before me. The two scenes were very close to each other in the movie, suggesting perhaps that the audience should also remember that the two scenes aren't identical. One actually happened and the other was what someone remembered as happening. Our memories can trick us sometimes.

Nice catch! I just watched this over the weekend and didn't notice the difference between the two scenes.and I was actually paying very close attention!
The only thing I'll add about the flashback scene is it seemed to come too early in the film; not much time passed between the original scene and the flashback scene. But I think it's a great film nonetheless!

This message has been deleted.

Yeah, you see this in a lot of movies with flashbacks. Especially Pulp Fiction. In that case, Tarantino said that the point was to illustrate how people remember things slightly differently from how they actually happened.
I'm not sure about that being the case here, but it might be a legitimate excuse. It doesn't really take any enjoyment out of the flick for me, anyway.