Hello!
I have J3.4.1 and K2 2.6.9
Creating a new K2 Item anch changing category, no extrafield Group if present.
It shows a message "This category doesn't have assigned extra fields" instead of loading the new fields for the new group.
Only after saving the extrafields Groups are available
Solved
It was only a permission issue. set 755 to plugin folder and files resolves the issue : in subfolder there is not script execution permission so Ajax.php always fails
Hope this help
