The following chapter:
displays badly in IE 11 (and presumably prior versions); the bullets from the bulleted list in the first para are rendered over the top of the Table of contents box which is floated to the left of them.
This appears to be a long-standing IE layout bug:
and a couple of workarounds are suggested there. The chapter page itself does not validate:
which I think should also be release blocking. We should only release valid pages.