Email forwarders created with a # symbol in the localpart are unable to be traced via the forwarders interface.

Symptoms

After creating an Email forwarder with a # in the name, you find that when you attempt to trace the forward, it silently fails. Within the cPanel error log, you may find the following is printed:

warn [Internal Warning while parsing [stdin] 31360] Use of uninitialized value $address in pattern match
(m//) at /usr/local/cpanel/Cpanel/EximTrace.pm line 68, <STDIN> line 1. at /usr/local/cpanel/Cpanel/
EximTrace.pm line 68, <STDIN> line 1. Cpanel::EximTrace::generate_trace_table(undef) called at bin/admin/
Cpanel/mailroute.pl line 84

Description

We've opened an internal case for our development team to investigate this further. For reference, the case number is CPANEL-50469. Follow this article to receive an email notification when a solution is published in the product. 

Workaround

At this time, no workaround is available for this behavior.