The frontpage slideshow with the template KeeSports changes randomly the text size as you rotate your iPhone or iPad.
There are no problems in desktop browsers.
What could be the problem?

Please provide us a link to your site.

It's a site in development so I can't provide the forum with a link.
But the problem seems to be solved but I don't know why.
In the template.css.php file at the Slideshow Container I added font-size:100%; and the problem was gone but after I deleted font-size:100% the problem was still gone. Also after I deleted browser history on my iPhone and iPad.

I’ve solved the problem. The problem also occured on another site.
It’s a mobile Safari issue.
I've added the following to the CSS-file and the problem was gone.
.slidetext {
-webkit-text-size-adjust:none;
}