This one is quite tricky.
I went there in early December: no sign with a name anywhere.

Yes, Beliris and Leefmilieu.brussels seem to call it that way.  There is also a collection of parks on anderlecht.be but this one is not in the list.  And ebru.be which is usually a reputable source calls it Rauter: https://www.ebru.be/Streets/streets1070/bruxelles-1070-parc-rauter.html

Decision: We’ll take your word and change the name.
Just in case, I put the former name (Parc Rauter - Rauterpark) as alt_name: searches on that name will continue working.