This issue relates to this issue. You need to install the Ahem font to be able to view this test case properly
There are several different combinations of conditions that can trigger this bug.
When hovering over the grey-colored area (with the words 'Hover here'), the color of the preceding inline box should not change to red.
For clarities sake, the preceding block-level sibling in the example below has been hidden. To trigger the bug, this hidden (or visible) element must have a font-size equal to, or smaller than the first child inline element.
Preceding block-level siblingX
The example below applies a border value to all four sides of the box, although only specifiying a border on one side will suffice.