I'll repost my answer from a related question here (since my question with more details is
probably soon to be closed) as suggestion for quick/possible fixes.
I've just ran into a Suggested Edit which present the same issue. The comment is barely readable, given that the 2nd (and subsequent) lines overlap half of the previous. This phenomenon also happens in the individual revision page.
The issue seems to be the CSS applied to the
Disabling/removing this entry makes the comment expand properly (along with several other element sizing on the page). Here's a screenshot showing the correct-looking comment:
An alternative solution (so as to not mess with the rest of the design) is to add
line-height: 1.4em; to the
revision-comment CSS class.