Breakpoint Ignored?

I am debugging VF11, cancel invoice, when I initially set breakpoints at statements = 'loop at' I continued until I finally got to the specific loop where it was looping and looping. However, the second time, when I put a breakpoint at that line of code it is ignoring it so the transaction is just clocking and clocking. Why didn't it stop at the line of code I set the breakpoint at?

Thank-You.