I also reached out to them on Twitter but they directed me to this form. I followed up with them on Twitter with what happened in this screenshot but they are now ignoring me.
That is 100% a bot, and whoever made the bot just stuck in a custom regex to match “user@sld.tld” instead of using a standardized domain validation lib that actually handles cases like yours correctly.
Edit: the bots are redirecting you to bots are redirecting you to bots. This is not a bug. This is by design.
The best way to validate an email address is to sent it an email validation link.
Anything outside of that is a waste of effort.
That is 100% a chatbot using a regex email validator someone wrote as a meme that the chipotle dev copied from stack overflow without context.