Delirium and Trail of the Sekhemas Time count down room some time cuz server problem

As mentioned, Delirium and Trail of the Sekhemas Time count down room some time cuz server problem. The problem shown as significant frame rate drop from 120+ to 10, pin goes up from 20 to 100+. Everything is slowed, animation time, movement, monsters, then after delirium end, or count down time ends, everything are fasting like 20+ time for 2 second. This isn't always happens, about 10% chance. Simulacrum seems happen more often. I thought was my problem, till I find this problem is better when there are less player online. Problem is better when after server restart.