Prohibition of duty drawback
Drawback of or exemption from customs duties at re-exportation allows materials, which would be subject to customs duties or charges in the EU, to be used duty-free or with partial duties in manufactured products to be exported to a third country. In the EU, the most common practical use of duty drawback or exemption is under inward processing.
Certain preferential trade arrangements prohibit the drawback of or exemption from customs duties on imported materials used in the production of products exported under preference. That means that in those cases customs duties for the imported materials may not be suspended or the materials may not be exempted from customs duties in the EU, and any duties on these imported materials must be paid if a document on origin is made out or issued.
You will need to check the specific conditions on this point, which are contained in the rules of origin of the relevant preferential trade arrangements.