An incorrect AnnotationClass ID is generated if the annotation is created from labels generated with the Maplex Labeling engine and a standalone Maplex extension is not installed.
Install standalone Maplex extension.**Please note: When multiple users access the same license manager, testing has shown that if there is only one Maplex extension installed and registered, it will be consumed by the first user without activating the extension from within ArcMap. Therefore, the second user will receive an incorrect AnnotationClass ID.