Issue Summary

If a username contains a pipe character, such as google-apps|jbiden, user mention linking will not be activated - the user mention will be rendered as is, e.g. 

[~google-apps|jdbiden]

Steps to Reproduce

1. Create a username with a pipe character, e.g. google-apps|jbiden
2. Try mentioning this user in a comment

Expected Results

Jira resolves the username and replaces the pattern with a user profile link. User will get an email notification about them being mentioned.

Actual Results

Mention pattern is rendered as is. No email notification about the user mention is sent.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available