Blast damage applied twice

Blast Damage don’t seem to work properly.
Refering to the ingame description, blast damage should be applied to each exposed body parts taking armor into acount.
Health pool should be reduced by the more damage recieve by a body part.

On a mission I play this morning, I had a new soldier with a sniper helmet and no armor on the body.
head 14 armors, 0 armor on the body and 140 HP.

he got hit with a grenade: 50 damage and 1 shred.
Only the body and the head have been hitten. Next turn I had 20 HP and bleading on the head. He lost 120 HP instead of 50.

The head was diseabled. The head should have taken 50-14 = 36 damage. The head have taken more than 40 damage.
the body has taken 100 damage.
100 +10 from max health +10 from bleading is 120 HP. The result is correct if the damage from the grenade was applied twice.

On the same mission an other guy took a similar grenade with 27 armor on the head. He recieve 23 damage => 50-27 = 23. This time the damage from the grenade was apply once.

On a stream I saw a grenade (50 damage) hits two soldiers. One had a sniper helmet and recieve 36 damage. Blast damage applied once.
On the same mission a grenade from a grenade launcher (60 damage) hit a Chiron for 64 damage and 32 shred. The chiron was hit at 3 legs and the carapace.
The legs have 30 armor.
first blast damage calculation => 30 damage and 16 shred
second blast damage calculation => 34 damage (preceding shred) + 16 shred
for a total of 64 damage and 32 shred

Once again the blast damage have been applied twice. But on the stream it was possible to see a difference. The first grenade hits the ground and the second grenade hits the Chiron.

So it seems that direct hit with a grenade apply the damage twice. I wonder if it is intended.