My pages include links to sibling pages; pages that are on the same level in the space hierarchy. The way I create these links is:

1. Click the Page Layout tool > Two Column Section with Right Side Bar.
2. Create a single-cell table in the right column. This is so I can color the background to visually separate it from the rest of the page. See attached image.
3. Create links to the sibling pages inside the table cell.
   After I save, the page looks as intended. However, the next time I visit the page (this can be days later) the page has removed the original first link and replaced it with a link to itself.
   In the attached image, the first link originally pointed to "Apache Mesos." Somehow, that link is gone and "Marathon" has taken it's place.
   When I run across this issue, I can go in and manually change the link back to the original sibling and that seems to stick.