Well I recommend this tutorial in regards to any lag related issues;
https://www.mpgh.net/forum/287-crossf...ucing-lag.html
You may PM me for further support along this tutorial.
To answer your question as to why;
After patches the servers themselves are "overloaded" and create a stressful environment for your computer - in addition Z8games has not done such a "great" job in this recent patch , they are still fixing issues, crashes, and content - hopefully they will sort these problems out soon.