my $t = localtime;
There are more moving parts than the minimum required to show the problem, which is surprising in such a short example script! The issue could as well have been illustrated using:
use strict;
use warnings;
use Time::Piece;
my $pattern = "%a, %d %b %Y %T %Z";
my $str = 'Wed, 13 Jan 2021 17:22:23 CST';
my $u = Time::Piece->strptime($str, $pattern);
print "Time is:\n", $u->strftime($pattern), "\n";
which doesn't give the trace back, but does show the error:
Error parsing time at d:/berrybrew/5.30.1_32/perl/lib/Time/Piece.pm li
+ne 597.
Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond