I have same issue. Last enemy has no health but no mater how many times he is hit he won't die.
https://imgur.com/a/DIM046u
Save file is here: https://drive.google.com/file/d/1Bfszn8Mcz3iBS7LRG0HfVBHjV6gSlYEP/view?usp=sharing
Do you need anything else?