I'm not sure exactly what this bug requires, but I've been able to reliably reproduce it in the question Is it acceptable to announce Area51 site in chat rooms?
I suspect it's reproducible only on questions with a small number of comments (4 in this case) such that the "X more comments" thing never shows up, because I haven't been able to reproduce it on questions with a large number of comments. It also requires a link to another Stack Exchange question.
This occurs in Android App v1.0.48 on a HTC One running Android 4.4.2.
Here's the bug and how to reproduce it. You can click the images for the full view.
1. Find a link in comments
This must be a link to another question, which the Stack Exchange app itself will handle.
Try the link in the last comment in Is it acceptable to announce Area51 site in chat rooms?
2. Tap the link, let the new question load, hit the Back button.
That's your Android phone's back button. There's nothing wrong with the question we visit. But when we return... the comments look like this.
That's it. This is really weird.