The instructions for installing solr with commerce seems to be incomplete.

The two config files in vendor/ibexa/commerce-shop/src/bundle/Search/Resources/config/solr/ ( in 3.x they are located in vendor/ezsystems/ezcommerce-shop/src/Siso/Bundle/SearchBundle/Resources/config/solr/ ) needs to be merged into the configuration.
This doesn't seem to be done by the bin/generate-solr-config.sh script.

So either the doc or this script needs to be updated