Nginx PageSpeed Sometimes CSS file doesn't load but it's rare

It's rare, but sometimes my page loads a blank white page with only the text content. That means the CSS file isn't loaded. This isn't a common thing and it happens VERY RARELY.

I'm trying to figure out what the cause is. The only things that I can think of that might cause this are Nginx PageSpeed and a local problem only tied to myself.



So I figure it's a Nginx PageSpeed issue?

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This is xenForo 2.1 while logged in if that's important. I also use the Redis code in my src/config.php file that was recommended here when xenForo 2 came around.

Because of how rare it occurs, it's not something I can test.