st: reshape value label bug?

[Jeph Herrin <stata@spandrel.net>]

I cannot reproduce this with any system or web datasets, but it
happens everytime for me; in the below I load a dataset, show that
there is no value label named -class2-, apply -reshape-, and suddenly
a new value label exists, and is assigned to my new variable _j. This
occurs whether or not I specify the variable with option -j()-.

What gives?

. u analytic, clear
. d, short

Contains data from analytic.dta
  obs:         1,653
 vars:            12                          11 Jan 2011 09:29
 size:        46,284 (99.9% of memory free)
Sorted by:  pat_id

. label list class2
value label class2 not found
r(111);

. reshape long payor_, i(pat_id)
(note: j = 1 2 3 4 5 6 7 8 9)

Data                               wide   ->   long
-----------------------------------------------------------------------------
Number of obs.                     1653   ->   14877
Number of variables                  12   ->       5
j variable (9 values)                     ->   _j
xij variables:
            payor_1 payor_2 ... payor_9   ->   payor_
-----------------------------------------------------------------------------

. label list class2  //????????????
class2:
           1 ACE-inhibitor or ARB
           2 Aldosterone Receptor Antagonist
           3 Beta Blocker
           4 Digoxin
           5 Loop Diuretics

. d

Contains data
  obs:        14,877
 vars:             5
 size:       312,417 (99.8% of memory free)   (_dta has notes)
-------------------------------------------------------------------------------------------------------------------------------
              storage  display     value
variable name   type   format      label      variable label
-------------------------------------------------------------------------------------------------------------------------------
pat_id          str9   %9s                    PT ID
_j              byte   %31.0g      class2     Corresponds to med group 
in Table 1
readmit30       byte   %9.0g       noyes      Readmission within 30 days
endpoint        byte   %15.0g      endpoint   Primary Endpoint
payor_          byte   %9.0g
-------------------------------------------------------------------------------------------------------------------------------
Sorted by:  pat_id  _j
     Note:  dataset has changed since last saved

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