Mu Origin Mobile - Dedicated Server Delay or Game Bug?

Can someone please watch the video and explain to me why are the monsters barely move? If you look at the ping, it doesn't seem to be an issue since I can warp, move to maps without delay, but whenever I use skills to monsters, it takes 2 seconds before they get hit but whenever I use normal attack, there is no delay.

My Dedicated server is as follows:

CPU: Intel Xeon E3-1245v5 - 4c/8t - 3.5GHz /3.9GHz
RAM: 32GB DDR4 ECC 2133 MHz
ISKS: SoftRaid 2x480GB SSD
Traffic: 3TB traffic - 250 MBPS

<font color="#122844"><span style="font-family: SourceSansPro">https://www.youtube.com/watch?v=jC_X...ature=youtu.be

Any help will be highly appreciated.