You mean that the bell icon moves horizontally around? For me, it’s the expected way, since the button is right-aligned. If the button was not resized, there was a white space on its right when the shorter of the two button texts is displayed, which may be quite large depending on the translation. For example, see Spanish:

The Unsubscribe (Cancelar la suscripción) link is almost twice as long as the Subscribe (Suscribirse), which means that the extra white space on the right is approximately two thirds the size of the button itself. For me, this would just look broken.

This didn't look that odd to me too.