bxl-forever
This is a known bug with StreetComplete.

The question relates to the node at the intersection of the road with the sidewalk along Rue Léon Theodor/Léon Theodorstraat.

The node was tagged as an "unmarked" crossing, exactly as you described it.
But StreetComplete is not (yet) aware of the difference between unmarked crossings and ordinary zebra crossings, and bugs users with this.

You can safely ignore such questions in the future.