There is no issue here.
Two different screnshots, so clearly not comparable situations. You can manually choose affinity for your city, which we see in the second screenshot - chosen earth and have the option to switch to fire.
In any other location affinity determined by the highest number of guardians of that affinity. If you have similar number of two affinities, like in the first screenshot - one earth and one water, your location gets no affinity.
Hello Archon. The reason for not having a dominant affinity is that you have 2 different affinities having the same numbers, so there isn't any dominant affinity. Dominant means the one which is superior in numbers to another, as the Archon CrazyBird already mentioned. Let's say if we have a dominant affinity, in our city, it doesn't mean that the same affinity will be applied where our units are stationed, except to our city. So, if you had your reinforcements to a pantheon or emporium, 2 different people sent guardians with different affinities, or, you sent 2 different waves of reinforcements to your own Emporium, with guardians having different affinities, so the one neutralised the other. It is a common mistake 😉