I've made a mob Exp grinder, where they spawn on the top of a enclosed paltform then fall down to a surrounded area where they can be attacked, upon which the experience balls/lights come to me but keep coming and do not end nor give any experience.

I thought it would give me experience and the balls would fade away untill they were all consumed so to speak.

What actually happend was the balls kept looping back and forth without doing anything whilst coming out of the gap in 2nd pic

Steps to Reproduce:

Place a double chest down and place stone/cobbletone either side, do the same making sure you have all 4 directions coverd.

Build each side up untill 18-20 blocks high

Starting level with the centre shaft, build 8 blocks out and repeat all the way around making sure there is a 2 block gap between each, so you end up with a + looking shape.

Repeat the process so each + line is 2 blocks high. Then proceed to fill the top line so you end up looking 3rd pic with a 8x8 square at each 4 places.

go out to a 8th block and build 1 more out then go 8 high and do so all around, then fill in roof... etc etc etc look at pic 3