Hi this unfortunately is an issue that we are currently aware of and are planning to fix in a future release. I'm not sure when the fix will be available or in which release but we do apologize for the inconvenience.
younity organizes music according to ID3 tags. As you have seen, if the tags on any given song in a compilation don't allow it to be associated with all the other songs in the compilation, they will appear as part of separate albums.
If you have access to an ID3 tag editor you can make sure that the Album field is the same for all songs that are part of a given compilation.