Monsters are not hit or in wrong coordinate

[sven-n]

Describe the bug
Either monsters are not attacked, or the monsters are walking to a coordinate which is too far off the "official" coordinate of the character.

To Reproduce
Steps to reproduce the behavior:

1. Go to spot with respawning monsters with a Blade Knight character
2. Start mu helper or another bot to do twisting slash continously
3. Wait until monsters accumulate which don't get hit anymore.

Expected behavior
The monsters should be attacked by the twisting slash skill. The skill hits are calculated on the server with a certain maximum range between monster and player coordinates.

Screenshots
See Youtube video.

[Niter88]

I was able to reproduce this behaviour by following the steps provided.
Can you point me to the method where this calculations occur?