EXTREME Mob LAG caused by Command Blocks

I have turned off all my command blocks and the LAG disappears. Anything that changes the scoreboard (or perhaps anything that engages with it) causes extreme LAG via the mobs, regardless if that particular mob is affected (involved) or not.

Whether scoreboard is the only thing causing the LAG in my world or not, free to add to this if anything new or relevant appears.

Mobs' movements become jagged instead of smooth.