[_eht]

The problem is that you are no longer compliant with the email spec: https://tools.ietf.org/html/rfc5322#section-3.2.3

Does nobody read RFC’s anymore?

[DarkWiiPlayer]

> Does nobody read RFC’s anymore?

I did, before posting my answer, though I admit I was too lazy to look up the email RFC and instead just used the URI RFC and assumed the allowed characters in the user-name would be the same :P