So I've purchased several boxes of Clearblue easy digital opks without any trouble. I had the digital part from the last box and this box on the shelf. I used one of them (not sure from which box) one day this week and after peeing on it the digital window showed all the symbols at once. I tried to stick the pee stick into the other one but it didn't work. I figured the digital part was at the end of its battery and I tossed it. Later I used the other digital portion with a new pee stick and it was flashing like normal but then didn't give a reading at all. No circle or smiley. I didn't toss that one because it's all I have left. I used it the next day and it seemed to work fine. Of course this all happened the day I was due for a positive! Thank goodness I had wondfos on hand. Has anyone else had problems like this? Do you think the digital things just have a short shelf life?