How to prevent funny characters on Home Page

I am building a site in the WP Twenty Fifteen theme.

I created a bare-bones minimum home page at https://bit.ly/1zlmpKS

The first time you hit the page, it looks fine. When you refresh the browser you get a series of funny characters like this.

How can I fix this?

**Amendment:**
Not sure how or if this relates and does what it does, but when I am logged into WordPress (as Super Admin) the home page never displays the funky characters. I can refresh and refresh and refresh dozens of times and it displays fine everytime. But the minute I logout of WP the home page shows the funny characters. I have an inner page on the new site as well, and it renders fine, consistently and all the time.

[1]: https://i.stack.imgur.com/4T6su.png

**Background & History:**
I started out installing the Quark theme. Then I created my own “starter” child theme for the site. I could never get the child theme to take until, say hours later, all of a sudden my child theme started working. So I continued trying to tweak the child theme just to see if I could use it as a building block for my new site. Admittedly, this is my first crack at using the Quark starter theme and my first attempt to learn and utilize a child theme. Well after days of frustration, I thought maybe the W3 Total Cache plugin was the issue. So I network-deactivated it. Still no luck. Then I pulled out the child theme and the Quark theme and simply went with the WP out-of-the box Twenty Fifteen theme. That’s when the funny characters surfaced. So I believe somehow and someway the W3 Total Cache plugin is messing with this network and the network site. I have dozens of other sites on my Multisite network install and none of them are misbehaving. W3 Total Cache is a standard plugin I activate for each new network I setup on my server. I have a shortlist of standard plugins I use across all networks and W3 Total Cache is one of them. Oh well…I am at a total loss.

**Something else that’s peculiar:**
When you hit the home page – it’s fine. When you refresh the home page it renders the funny characters. But then if you wait for 5-10 mins and hit the home page again it renders fine. What might that mean in the WordPress world?

**Next Trial & Error Test:**
I just re-installed Quark theme and network activated my Child Theme. The theme works — so it is not a theme issue. The funny characters still appear on the home page on refresh under the Quark Child Theme. So it is some sort of unexplained caching issue, I think.