There is even a Wikipedia article on Free word building in Interlingua stating that it is feasible to apply derivational affixes in Interlingua productively even when none of the so-called control languages uses a specific derivation.
However, the Wikipedia article has a lack of real-world examples of such Interlingua words. How productive is Free word building in Interlingua? What are some sample words that are actually used in Interlingua?