Trouble with state and module-begin

mb-st.rkt

#lang racket/load

(module st racket
  (define is-typed? (box #f))
  (define type-env (box 0))
  (provide is-typed? type-env))

(module mac racket
  (require (for-syntax 'st))
  (define-syntax (m stx)
    (unless (> (unbox type-env) 0)
      (displayln ">> type-env is 0")
      (error 'fail))
    #'#t)
  (provide m))

(module lang racket
  (require (for-syntax 'st))
  (provide (rename-out [mb #%module-begin])
           (except-out (all-from-out racket) #%module-begin))
  (define-syntax (mb stx)
    (displayln ">> in module-begin")
    (set-box! is-typed? #t)
    (syntax-case stx ()
      [(_ forms ...)
        #'(#%module-begin 
           forms ... 
           (begin-for-syntax
             (when (unbox is-typed?) 
               (set-box! type-env 1))))])))

(module A1 'lang
  (require (for-syntax 'st))  
  (require 'mac)    
  (module+ sub
    0
    (m)))

(require 'A1)