If the bundle writer creates a project in Eclipse with ecl-bundles as the source folder, or adds ecl-bundles as the source folder to the ECL-IDE, the import paths will be different then they will be when the Bundle is installed.

The bundle writers guide (https://github.com/hpcc-systems/HPCC-Platform/blob/master/ecl/ecl-bundle/BUNDLES.rst) should include some advice on project set up. The bundle writer must add the bundle folder as the source folder to have the same import paths for the attribute when installed as a bundle.