It is interesting to note that a Devel::Peek::Dump done in 5.16 also shows UTF8, but 5.16 does not have the problem that 5.18 does.

C:\Users\gweekly>c:\ActivePerl5.16.3\bin\perl -d i:\bin\badperl

Loading DB routines from perl5db.pl version 1.37
Editor support available.

Enter h or 'h h' for help, or 'perldoc perldebug' for more help.

main::(i:\bin\badperl:16):          if grep { /^ SAM $ /xmsi} keys %ENV;

  DB<1> c 27
main::(i:\bin\badperl:27):      my $fixed = substr "X$name", 1; # Should be the
same

  DB<2> use Devel::Peek

  DB<3> Dump $name
SV = PVNV(0x2cc711c) at 0x2a27314
  REFCNT = 2
  FLAGS = (PADMY,POK,pPOK,UTF8)
  IV = 0
  NV = 0
  PV = 0x2d6614c "SAM"\0 UTF8 "SAM"
  CUR = 3
  LEN = 12

  DB<4> q

C:\Users\gweekly>c:\ActivePerl5.18.1\bin\perl -d i:\bin\badperl

Loading DB routines from perl5db.pl version 1.39_10
Editor support available.

Enter h or 'h h' for help, or 'perldoc perldebug' for more help.

main::(i:\bin\badperl:16):          if grep { /^ SAM $ /xmsi} keys %ENV;

  DB<1> c 27
main::(i:\bin\badperl:27):      my $fixed = substr "X$name", 1; # Should be the
same

  DB<2> use Devel::Peek

  DB<3> Dump $name
SV = PVMG(0x2f14534) at 0x2bfd924
  REFCNT = 2
  FLAGS = (PADMY,POK,pPOK,UTF8)
  IV = 0
  NV = 0
  PV = 0x2f730d4 "SAM"\0 UTF8 "SAM"
  CUR = 3
  LEN = 12

  DB<4>