Wrong E-mail address format when updating issue

[Simon Marchant]

When updating an issue with an unconventional email address in Jira Service Desk 4.6.0 I am getting the "Wrong E-mail address format".  This is triggered from the Edit button on a service desk task but also from create linked issue.

I vaguely recall setting a regex on the field some years ago, but cannot find where for the life of me. 

If anyone has any insight as to where regex's are implemented, I would be indebted to you.

Thanks in advance.

[Brant Schroeder]

@Simon Marchant 

This is usually done via an app like Power Custom Fields.  Do you have anything like that installed?