Size of like-button changed on mobile devices

I've been displaying a like-button on my mobile websites for quite some time now using an iframe. For a few week开发者_如何转开发s now the size of the button has increased on all mobile devices, but not on for example the iPad or desktop browsers. Does anyone know why this is happening or what I can do to show the old size, because that fitted perfectly. Now it's too big for it's container.

Thanks in advance, Cyril

Seems like a bug you should log with Facebook. Log it at: https://developers.facebook.com/bugs