Two instances of single form on one page causes no validation on second block

I have one form that is displayed twice on a single page as blocks via multiple contexts. The blocks are in separate regions.

If only one instance of the form is on the page in any region, validation works properly. Once a second form is added to the page, the block that appears later in the markup will lose the validation from the module. Some validation rules are picked up due to the browser recognizing HTML5 attributes like `required` - but this validation is not from the module and is not consistent with the module's validation or across browsers.

Ideally, multiple instances of the same form on the same page should still work properly.

Marketing people love to put their call-to-action forms all over the place, you know?