Target release bug
I notice this the most in TA when you kill the blooms.
You guys need to learn to optimize, and stop doing several threads for the same topic:
https://forum-en.gw2archive.eu/forum/support/bugs/TA-Blooms/first#post2350535
or
https://forum-en.gw2archive.eu/forum/support/bugs/Mobs-enemy-spawns-not-registering-dead/first#post2314969