In the old versions of Aspose.Words, the bookmarks at Block, Cell, Row levels were not supported. So, the bookmarks were moved into the next nearest paragraph on document import.
We added LoadOptions.AnnotationsAtBlockLevel property in old version of Aspose.Words to keep the old and new behavior of Aspose.Words. We also added in release notes that this property will be obsolete in future.
In the latest version of Aspose.Words i.e. 21.4, the bookmarks are imported correctly into Aspose.Words’ DOM. So, there is no need of LoadOptions.AnnotationsAtBlockLevel property.