Hello,

I am afraid this edit is not correct.

The shape of those two buildings was correct, it was imported on the official building outline matching government data.  The "spike" really exist, it was not a mistake.  The correct outline can be found on Digitaal Vlaanderen GRB imagery, which is the official source for this part of Belgium.
https://www.openstreetmap.org/way/513036904
https://www.openstreetmap.org/way/513036905

This MapRoulette quest is apparently encouraging users to blindly "fix" buildings everywhere, even when there is no need.  Please make sure to inspect source data correctly, and mark them as false positives in MapRoulette in cases like this.