ᐅ Plaster or Wall Crack

Our house is now almost 6 years old, and fine hairline cracks have repeatedly appeared on the exterior plaster from the beginning, especially on the gable walls. The construction management at that time had the cracks repaired repeatedly. This year, for whatever reason, the previously repaired cracks have reopened, as they do every year, along with countless new ones. But in my opinion, the worst thing is that we have now discovered three cracks running through the entire masonry. This means that the cracks visible on the exterior plaster continue inside the walls behind two radiators in the interior plaster, and one is visible through the cracked textured wallpaper on the gable ceiling. The house was built in three months using Ytong blocks. Such cracks are not normal anymore, right??? They are not wide—only 1-2mm (about 0.04-0.08 inches)—but they go through the masonry?? By the way, in case it matters—90% of the cracks are on the gable side facing southeast, and 9 meters (about 30 feet) from this side there is a road. How does warranty coverage work for such cracks? Re-sealing the cracks has not improved anything and certainly has not lasted. What else can we do? Thanks in advance.