When you attempt to select a block, or a groundcover, site, or RefNote hatch, you are unable to preview the hatch correctly. When you scroll down in the dialog box to select blocks or hatches, many of the slides will have identical appearances but different names. Further, when you select a block or hatch in the dialog box, the thumbnail preview doesn't match the block or hatch as placed in your drawing.
Note in the example below that several of the hatch preview slides have the same appearance but different names.
This issue can occur when the system is unable to download the preview slide (.sld) files properly.
You'll need to confirm you have full read/write access to the LandFX folder – specifically, the folder containing the block or hatch you are trying to access (example: LandFX/Hatch/Site).
As a test, you can temporarily move all files from that folder to a different location, to find out whether they downloaded correctly. Once you move these files, the system should automatically download them again. If it doesn't, you are likely facing a permissions issue. You may need to contact your IT administrator to request full read/write permission for your office's LandFX folder, along with any subfolders.
If you can confirm that you have the proper permissions for the Hatch folder and its subfolders, and you're still facing this issue, you may need to re-download the hatch slides (SLD files).