Parts of the EU say that, then at other times other parts act inconsistently with it. I was just at a meeting of an EU body where it was emphasized that, when considering the language of European patents written in English, courts would deliberately interpret the text as having been written by a native English speaker, even when it was clear that the author was a native speaker of a different EU language, for example, in cases where the author was clearly following a grammatical convention of their native language (eg, in comma placement) that might be awkward or ambiguous in English.

While that might make sense from a legal standpoint, it seems like it makes it risky to hire patent lawyers in Europe who are not native English speakers, which in turn, along with many other similar inconsistencies, does in practice create an EU-preferred language.