Submit contact button from product contact page disapeared

-- url of the page with the problem -- : www.atmospheredailleurs.com/collections/...uct/contact/cid-1337
-- HikaShop version -- : 2.6.4
-- Joomla version -- : 3.6.4

I'm still wandering why...
It doesnt come from a view override, i tested it (deleting all my overrides), but maybe from a js issue.
As this option isnt activated on the demo website, i cant compare with mine.