Cursor is moving slowly while it is attempting active scan to our systems

Hello,

We are using Symantec Endpoint Protection 12.1 RU 4 and has been successfully updated the latest version also. After that I am facing this issue. Some users in the network there systems getting hanged up for 2 min like cursor is moving slowly for 2 min and after that it is working fine and for some users it is happening for every one hour or two hour. Can any one help me on this issue.