The first time you click the text grey’s out a bit like placeholder text but is still typable. It does nothing else until clicked again.
I have only tested on Firefox mobile so far.
I suggest you either try to replace the ‘mouseover’ effects with css :hover effects or trigger the jQuery event only, if the user is not on a touch device.
A third way can be found on the page over at stackexchange that I linked above: add a jquery snippet that tells the (iOS) browser the link was actually clicked.
PS: it could be useful anyways if you could either provide code or name any of the contact form plugins you used.