You can hit people before grace period ends and usually I also tend to get these particles when an invisible person is running away from me.

 

I understand what kuke is trying to say. If I hit an invisible person, sometimes it only drops the splash potion with no hit/damage given to that user. I can confirm this because I have CC++ and I use it every game and when this happens to me, when a hit is registered but no damage given, they aren't lit on fire. That's what kuke is trying to say, I think :p.

 

Hm, I can't think of any normal situation where the player wouldn't get damaged, and the splash potion effect shows.

Actually I'm fairly sure the only case where this could happen is when nocheatplus detected an overreach hack, and blocks the damage.

I'm going to close this topic, since the suggested change has been applied. If it is still an issue after the update goes through, reopen a suggestion with some suggested (possible) changes.