The attached script creates calls symtable.symtable many times on a code snippet that contains a single class with a method called "top", and some other important (to trigger the behaviour) properties:
  * a class variable
  * at least three other methods

The symtable module is reloaded each time, which seems to exacerbate the problem, but it not necessary.

The return value of symtable.symtable is sometimes a SymbolTable object, as expected, and sometimes a symtable.Function object.

Here is some example output from the script:

c:\Python27>python.exe C:\Temp\symtable_weirdness.py
Counter({'SymbolTable': 59, 'Function': 41})

c:\Python33>python.exe C:\Temp\symtable_weirdness.py
Counter({'SymbolTable': 89, 'Function': 11})

The values are consistent between runs, but can be changed by altering PYTHONHASHSEED between runs.

New changeset bc259b221cb8 by Benjamin Peterson in branch '3.3':
just return toplevel symbol table rather than all blocks (closes #19393)
http://hg.python.org/cpython/rev/bc259b221cb8

New changeset f1b7b5979e96 by Benjamin Peterson in branch '2.7':
just return toplevel symbol table rather than all blocks (closes #19393)
http://hg.python.org/cpython/rev/f1b7b5979e96

New changeset f5c729dbe9fb by Benjamin Peterson in branch 'default':
merge 3.3 (#19393)
http://hg.python.org/cpython/rev/f5c729dbe9fb