For Map to Bean mappings like
@Mapping(source = "exDate", target = "exDate", dateFormat = "yyyy-MM-dd")
@Mapping(source = "payDate", target = "payDate", dateFormat = "yyyy-MM-dd")
@Mapping(source = "recordDate", target = "recordDate", dateFormat = "yyyy-MM-dd")
@Mapping(source = "annDate", target = "annDate", dateFormat = "yyyy-MM-dd")
public abstract CorporateAction toCorporateAction(Map<String, String> rowValues);
the plugin flags all source properties as "unknown". The source property inspection should probably be skipped in this case (When source object is a Map<String,?>) since it can't possible know the contents of maps passed in.