Have you seen? That’s a little bug that happens to be harassing me for quite a while – let’s say some months.
I suspect that that’s because this WordPress installation is part of WP network served but NGinx but I’m not sure. Some days ago I gave it a quick glance, thinking the theme was to be blamed, but couldn’t find anything.
I shall investigate ASAP, after I finish a couple of more important tasks.
Currently I use nginx http server. I’ll try to switch to apache to see if it solves the issue