Why did I get peak on one test and not the other??

Hello,

So I am using clearblue advanced ovulation tests, I have tested for 3 days and got high lh. Then I needed new test so I bought a new package. I used that one and it came back with an empty circle twice, but on the old test stick it came back as a solid smiley. I used the new one again the next morning to test it out and it came back as an empty circle. I am confused. Am I ovulating or not??