Last modified: 2013-04-25 22:46:48 UTC
e.g. inserting <p>c</p><p>d</p> into <p>ab</p> between a and b results in <p>a</p><p>c</p><p></p><p>d</p><p>b</p> This is because fixUpInsertion fixes c & d separately and after inserting c (by closing out a) it decides to re-open the paragraph it closed (sensible), but the d comes along as splits that new paragraph (not sensible), resulting in a blank paragraph between the two.
https://gerrit.wikimedia.org/r/#/c/55791/
NB: this bug is not restricted to paragraphs