Help!!

Amber • Loving and learning! :)
Is it normal for your ovulation test strips to be consistently darker in the morning than in the afternoon/night? I see other strip photos gradually get darker nearly every day during the fertile window, but mine go from dark to light to dark again the next morning. This is my first time using a kit like this. I test at about 10:30am, mid-afternoon sometimes, and around 8pm every day right now.