handling of this strange(?)

I've had the problem in a big function and reduced to show the problem.
Simple example for the need could be to

• have a blinker running
  
• need the status of the blinker somewhere else in your code
  Right now I help my self using a get-function, instead of b.a
  Any handling of a (line 5 and 6) should cause an error in my understanding.
  In jsfiddle it does.
  Before running this short example my board(32STMF4Discovery) was disconnected and "reset();" was sent in terminal window, before transfering the source above.