The issue
When two contributions had the same title a bug was causing the links to point to the same content. This means that the in some cases, the contribution was being shown with the wrong author. Here's the GIF showing the problem:
Solution
The bug was caused by a wrong query in the contributions to find the correct contribution to render. To show the proper contribution the query must include the author name and the permlink. But the first one was being ignored. In most cases, this wasn't a problem because the permlinks usually are different from each other, but there are cases that they are the same.
Links
Posted on Utopian.io - Rewarding Open Source Contributors