XF 1.4 Thread Tooltips work for parent but not child - Can't find why

Joe Link

Well-known member
Using XenBase for the parent and thread preview tooltips work fine when hovering over a thread. Using the child they don't work, and I can't seem to figure out why. I searched each style for templates with PreviewTooltip, but couldn't find any differences that would pertain to the tooltips.

How should I go about tracking this down?