Long comment headers display badly on narrow screens
Using the black theme on my phone, a comment which had a long datetime and edited datetime overflowed to two lines, and the background did not extend far enough - the result looks quite unpolished.
Interestingly, when I tried to recreate this on my desktop, the datetimes shortened to the abbreviated form "18h 8m ago". I think the reason for this is the abbreviation is triggered by a certain pixel width threshold.