The issue is that your other css styles on the site are being applied to the form, which is affecting its behavior. If you check out the version of your form hosted on Feathery, you’ll notice that it’s working the way you expect.
You have a style that applies a background color on input elements like email, which is covering the placeholder.
You have a style that sets text areas to 160px height.
I’d recommend you disable both and apply those styles directly through Feathery if you want that behavior