Are you trying to do a Live or an Offline migration?
When you create a live migration package, Pulse does not migrate data ( .cub file are not migrated). For attributes it’s different because attribute definition is stored .dimx file and attributes values is stored in .dimd:
During an online migration:
If the dimension has less elements than MaximumElements parameter value in Pulse.cfg (by default it is set to 5,000), then Pulse will create the dimension, create the elements and then populate the attributes.
If the dimension has more elements than MaximumElements value, the dimension will be created without any elements so attributes won’t be migrated as-well.
For offline migration, the }ElementAttributes_ cube should be included in the package:
I hope this help,