Just FWIW: problem occurs with with AS 5.24 on Win 7-64:

C:\>perl -v * This is perl 5, version 24, subversion 0 (v5.24.0) built for MSWin32-x86-multi-thread-64int on Win 7 pro, 64bit

#!/usr/bin/perl

 use v5.10;  # (OP's code, verbatim)
 use strict;
 use warnings;
 
 use Data::Dumper;
 use DateTime::Format::Strptime;
 use Time::Piece;
 
 $Data::Dumper::Sortkeys = 1;
 
 my $date = '05/10/1969';
 my $ymd = '%Y-%m-%d';
 my $mdy = '%m/%d/%Y';
 
 my $t = Time::Piece->strptime($date,$mdy);
 
 say $t->ymd; # Prints as normal
 say $t->strftime($ymd); # Segmentation fault
[download]

Execution:

C:\>F:\_Perl_\PMonks\1194689.pl
1969-05-10

C:\>

And, the same popup as cited above with the following content:

Problem signature:
  Problem Event Name:    APPCRASH
  Application Name:    perl.exe
  Application Version:    5.24.0.2400
  Application Timestamp:    578689b9
  Fault Module Name:    Piece.dll
  Fault Module Version:    0.0.0.0
  Fault Module Timestamp:    57868a01
  Exception Code:    c0000005
  Exception Offset:    00002398
  OS Version:    6.1.7601.2.1.0.256.48
  Locale ID:    1033
  Additional Information 1:    0a9e
  Additional Information 2:    0a9e372d3b4ad19135b953a78882e789
  Additional Information 3:    0a9e
  Additional Information 4:    0a9e372d3b4ad19135b953a78882e789
[download]