I started having this issue and when I removed MCBans the issue went away. Now that I have it back in the issue is once more occurring. I also have intermittent lag that seems to be mitigated when MCBans is not in. Is there anything in the plugin that could be causing this if it has to wait for a response from your servers? If so, is there anyway to make it so it doesn't hold everything up while it waits for the response?

CraftBukkit #2120 MCBans 3.7

Here too!!!