[web2py] bug? - boolean field automatically toggles in forms when validation fails

[Carlos]

Hi,

Boolean fields are automatically toggling in forms when validation fails.

(model)
   db.define_table('xxx', Field('xstring',requires=IS_NOT_EMPTY()), 
Field('xboolean','boolean'))

(controller)
   def xxx(): return dict(form=crud.create(db.xxx))

(url)
   http://localhost:8000/test/default/xxx

When form is initially loaded, the boolean field is OFF, but after hitting 
submit (with a failed validation, e.g. xstring empty), it automatically 
toggles its value to ON, then hit submit again and it toggles to OFF, and so 
on.

This occurs in both: creates and updates.

Is this a bug?.

Thanks,

   Carlos