All DSpaceObjects have two flags for modification: isModified and isMetadataModified. The current behavior is inconsistent. isMetadataModified gets never reset once the flag is set by modifying the metadata, even after the object is persisted using the update method of the corresponding DSpaceObjectServiceImpl. isModified mostly gets reset in the update method, but at least here: https://github.com/DSpace/DSpace/blob/8a48f78/dspace-api/src/main/java/org/dspace/content/CommunityServiceImpl.java#L257-L267 the logic seems wrong.
The handling of the two modification flags of the DSpaceObjects should be checked.