I agree.  There is some incoherence here.  The official map on ville30.brussels shows the whole street at 50 kph but unless the digital signs show "50" it is not allowed to drive faster than 30 kph.

Until they fix this problem, maybe we could set the whole street with maxspeed=30 + source:maxspeed=BE-BRU:urban (between Vervloesem and Saint-Lambert).