While unsure about what is going on, i must admit that was a totally unexpected result

i was wondering if you had run into something called a dualvar.

  use strict; use warnings; 
  $|=1; 

  use Scalar::Util qw(dualvar);


use Devel::Peek;
print "nv1\n"; my $nv1 = 1e-2                 ;Dump($nv1); print "nv1:
+$nv1 ".($nv1+0)."\n"; Dump($nv1); 
print "dv2\n"; my $dv2 = dualvar( 1e-2, "hi" );Dump($dv2); print "dv2:
+$dv2 ".($dv2+0)."\n"; Dump($dv2);
[download]

Result

nv1
SV = NV(0xa7c024) at 0xa3e614
  REFCNT = 1
  FLAGS = (PADMY,NOK,pNOK)
  NV = 0.01
nv1:0.01 0.01
SV = PVNV(0x3f7364) at 0xa3e614
  REFCNT = 1
  FLAGS = (PADMY,NOK,pIOK,pNOK)
  IV = 0
  NV = 0.01
  PV = 0xa959d4 "0.01"\0
  CUR = 4
  LEN = 36
dv2
SV = PVNV(0x3f73c4) at 0xa8facc
  REFCNT = 1
  FLAGS = (PADMY,NOK,POK,pNOK,pPOK)
  IV = 0
  NV = 0.01
  PV = 0xa45c5c "hi"\0
  CUR = 2
  LEN = 10
dv2:hi 0.01
SV = PVNV(0x3f73c4) at 0xa8facc
  REFCNT = 1
  FLAGS = (PADMY,NOK,POK,pIOK,pNOK,pPOK)
  IV = 0
  NV = 0.01
  PV = 0xa45c5c "hi"\0
  CUR = 2
  LEN = 10
[download]

Of particular interest here is the line "dv2:hi 0.01" where in string context you get hi, but in numeric you get 0.1. But it doesnt seem that dualvars are your problem.