Recently, I watched the How I Met Your Mother episode, "The Poker Game"(S09E05), when my sister pointed me out this jarring inconsistency from approximately minute 09:56:
Here, you could explicitly see Katie Holmes' character, Naomi/The Slutty Pumpkin, who Ted won't encounter again until Season 7. This scene was a flashback; but here's the inconsistency:
When did this particular scene take place, exactly?
It was mentioned to take place a good number of months, perhaps at the most a year, after Lily and Marshall's marriage, but prior to Ted's engagement with Stella, putting it somewhere in between the middle of Season 2 to the end of Season 3. However, the presence of The Slutty Pumpkin begs to differ. One might argue Ted didn't notice her, played for humorous effect, but then in this scene shouldn't Ted be wearing that sandwich-board like costume?