Freezing Midgame

So is lately I have a problem of freezing mid game that happen whenever someone joined the world. As I observe, this occur whenever I add in command blocks to my world and and the freeze occur between 30 second mid game. I have a strong device and plenty of storage space to play with. This is a serious bug because if this occur I may not be able to play with my friend and enjoy the content you guy put to the table.