With 1.3, the incubators were changed to guarantee/focus on Exclusive dinosaurs based on the Arena you are in. This means, at Arena 5, epic incubators will award Stygimoloch(the last/only epic up to Arena 5), rare incubators will award Irritator Gen 2(the last/only common available up to Arena 5), and common incubators should award Irritator(the last rare unlocked IN Arena 5).
However, after opening close to 15 Common Incubators, I consistently get Purrusaurus instead of Irritator DNA. Has anyone else noticed this? I wanted to sit in Arena 5 to farm both Irritator DNA with the new incubator mechanics, but I have yet to get Irritator Gen 1 DNA after 2 weeks.
Edit: In fact, when you preview the incubators, the common doesn’t even mention giving exclusive DNA like the other two do.