Email address validation is broken

[dustinkerstein]

When entering an invalid email address, there is no validator popup (unlike when it is left email) and the form allows submission but throws a server error:

Server Error
Sorry, something went terribly wrong!

0 - Address in mailbox given [XYZ] does not comply with RFC 2822, 3.6.2.
For further details please review your logs/ folder, or enable displaying of errors in your system configuration.

I've ensured that I have updated to the latest Grav and plugin versions, and I haven't been able to replicate this on a vanilla Grav install + the Form plugin.