Css / js malfunction on load

I’m apparently having the same problem now on multiple sites. I create basic css to center buttons. When the page loads, the css of addtoany and other nearby elements is screwy. When I open devtools to inspect the problem, it immediately goes away and I cannot debug! It’s happening across all devices and browsers I’ve tested so far.

It happens on a site we use for our online store (self-hosted third-party software) and I thought I’ve been losing my mind. ..but I’ve installed the plugin on our wordpress site and it’s doing it there too!

Without debugging options, I don’t know how to handle this.