Damage Delay?

So I was using the little uppercut thing that throws them into the air and all, but the ceiling above the mob I used it on was right above it. This caused the uppercut thing to throw them up against the ceiling, stall for like a full second, then explode twice extremely fast as it should have exploded once at the top and once when it hit the ground.
I couldn't see the damage that it did since the text went into the wall, so I couldn't tell if it took the damage from both explosions or from just one. I was wondering if there is actually a delay in the amount of time that a mob can take damage (not like attack speed, just damage from any/all sources.)

ALSO
I was playing around with uppercut after cuz why not, and I found out that I was able to uppercut a mob, and when it came crashing down to explode, if I timed the uppercut fast enough, it wouldn't explode and would bounce up again in another uppercut cycle. I was also wondering if the damage from the first uppercut ground explosion carried over and did the total damage that it was supposed to after the second uppercut, or if that damage got skipped.

Sorry for the horrible explanations, I tried to word it the best I could :/

 

The uppercut works in a way so damage will be dealt upon the initial hit (the line of ground breaking, throwing the mob into the air), when it has flown for a second or two making the firework effect, and lastly when the mobs hits the ground.

In your first example, the mob did take the damage it was supposed to take. The last hit in the cycle is dealt without relation to the first, nor second hit. It is just when it hits the ground.

In the later example, the mob did not hit the ground as it was supposed to, and thus the damage it should have taken was cancelled. Damage does not stack like that.

I hope that helped.

 

thanks, that really helped