I choose the small cup for stronger coffee but changes

I have a B60 Keurig, I had it for about 5 months now, lately when I put the Kcup in the Kcup holder then push the handle, I select the small cup for stronger coffee. It will drip for about a second then stop, I would open the handle reposition the kcup and close the handle again, then it start dripping again, but the small cup is no longer lit, instead the big cup is lit, it makes it a weaker coffee. Help has anyone have it happened to them. Thank in advance for your help.