Form (I don't need more characters)

Description of the issue:
When filling out this form http://theprintedgarden.com/contact.html, with Brave, nothing happens when I hit ‘submit’.
When I fill out the same form with Vivaldi, after hitting ‘submit’, the form disappears, and a ‘thank you’ message appears

Exact URL of the website in question:

Did the issue present with default Shields settings? (yes/no)
Yes

Does the site function as expected when Shields are turned off?
Yes

Is there a specific Shields configuration that causes the site to break? If so, tell us that configuration. (yes/no):
I don’t know. There might be. I’m too lazy to check out. It’s Brave’s job to know such things

Does the site work as expected when using Chrome?
I don’t know. I do not use Chrome. I’m too lazy to install chrome for this issue

Brave version (check About Brave):
1.35.72