Customize page problem

Hello! When we try to customize the web site it goes blank intermittently, as if it updates all the time. We tried to disconnect all the plugins and connect them one by one to see if any of the current ones that we use is causing the problem. But it seems that the plugins aren’t the problem. Sometimes the blinking goes away by itself but shortly after returns after every change we make or after refreshing the page. How could we solve this problem? Thanks!

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