The email verification “ValidEmail” on forms is not 100% correct. It is marking emails with apostrophes as invalid. It appears that ValidEmail is using the Regex
/(^[a-z0-9]([0-9a-z\-_\.]*)@([0-9a-z_\-\.]*)([.][a-z]{3})$)|(^[a-z]([0-9a-z_\.\-]*)@([0-9a-z_\-\.]*)(\.[a-z]{2,4})$)/i
instead of
/(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])/
this also appears in grid. It should probably be fixed so the validation isn’t giving false negatives.