I got the following warning:
Warning message
The client-side hierarchical select widget cannot be used for the commerce_product -> xxxxxx -> field_location because it is not using the default entity reference selection handler or has no taxonomy vocabularies selected. If you are aimed to use the CSHS widget for the Location field, please configure it accordingly or ignore this warning as its purpose to let site builders know why the CSHS widget is not an option for this taxonomy reference field
The above warning makes the CSHS option is not available for the field.
1. Install and enable CSHE
2. Go to Commerce --> Product Type to manage the the taxonomy term field.
Closed: works as designed
4.0
Code