Hi @tubby,

Please leave your forum URLK to allow us to debug the CSS conflict. 

I switched to WordPress twentyseventeen theme and the problem is gone. But with the Hueman theme the problem exists.

Inside the CSS of Hueman I found this:

.far, .fab, .fas {
width: 1em;
text-align: center;
}

Without the width style, all works fine.

Based on the knowledge, I can solve the problem by myself. Thank you for your assistance.