Illaoi tentacle hits with less dmg after the first one

Pretty much thats it. If you, for example, W an enemy and Q right after it, the Q does MUCH less dmg. If the tentacles hit the target at exactly the same time the dmg is fine. That is a small time window. Around 0.01-1 second. After that time the next hit deals full dmg again.

That is since a very long time or since release allready. Not just because of the last patch. I thought it was intentionally, but u cant read smth about it.