I'm not sure if this is a bug or a feature but one of our users asked me and I said I'd try and find out. Here's a step-by-step -
- The user liked a post in a thread.
- The user looks at the liked message and sees "Username, X and Y and 2 others" next to the like icons.
- The same user likes another post in a thread.
- Now she's seeing "You, X and Y and 2 others" next to the like icons.