Drop-down list non displayed in catalog UI

Hi experts,

We are having the following issues with SRM-MDM Catalog 7.02.

We defined via MDM Console 2 lookup fields, and made the relevant settings in the catalog UI to display a drop-down list for those fields, in order to use them to filter catalog items.

In development system it all worked fine, but we made the same configuration in quality system and for each field a "checkbox" is displayed, instead of a drop-down list (see screenshot attached).

The select logic works fine, but how can we display the standard drop-down list? Is there a specific parameter to set?

Thanks a lot!

Ci