The most likely cause for not seeing the bookmarks when viewing a Keystone issue is that they have been turned off in Acrobat. Fortunately, it is easy to toggle them on or off, and this should be the first thing to try.
The easiest way to turn bookmarks on or off is to click on the Toggle Bookmark View icon in the Side Panel Control Panel located on the far right side of the application window in newer versions of Acrobat or the far left side of the application window in older versions of Acrobat. The icon will look similar to this
in newer versions of Acrobat or this
in older versions. Each click toggles the bookmark panel between being visible or hidden.
Should you not see the icon, you will need to activate bookmarks control by clicking on the Bookmarks submenu item, which is, depending upon the version of Acrobat you are using, located in a submenu similar to one of these:

The one on the left is typical of newer versions of Acrobat, while the one on the right is typical of older versions. Make sure that the check mark to the left of Bookmarks is visible, if it is not, then click on the Bookmarks item.
Once the check mark is visible, you should see the Toggle Bookmark View icon in the side panel and can then toggle the actual bookmarks between being visible or hidden.