Chain command blocks execute in same game tick, but a discrepancy is observed between two command chains that should act identically

When summoning a lightning bolt and killing it during the same game tick (using a chain command block and repeat command block) there is a discrepancy in the number of entities displayed.

All command blocks activated with 30 game tick pulse from wood button.

Signs are placed next to the command blocks to show the commands in each.

Leftmost: Intended behavior; summons 30 lightning bolts and displays all

Middle: Repeating command block set to summon, chain block set to kill; displays 3 bolts with no sound

Rightmost: Repeating command block set to kill, chain block set to summon; displays a reduced number of bolts with sound, command block log in previous tests shows that all bolts were killed.

video at low resolution because of 10mb filesize limit