Not sure where else to actually submit a bug report for AGX.
This issue relates to the nmf file becoming corrupted after editing the attributes of multiple text notes that are located in a folder.
1. Open a new map
2. Create a few map text items.
3. Create a folder
4. Move the text items into the folder
5. Select all of the text items. Right click and change one of their attributes such as size or font
AGX changes the attributes but also creates copies of the text items in the root of the content window. If you save that nmf, close AGX, then try to open the nmf, AGX tells you the file is corrupted. You can manually edit the nmf file to remove the spurious text items it created in the root of the content window and the nmf becomes usable again.