Facebook Ads testing question

I’m testing two versions of a book cover using Facebook Ads, and I’m running into a bit of a problem. One of the versions looks like it is performing better because it has a lot of clicks. But that one also has way more impressions, so when I dive deeper, the second version (with fewer clicks) actually has a higher click-through rate.

What I can’t figure out is why the second version is being shown so much less than the first. Am I competing with myself for impressions by running two ads to exactly the same audience at the same time with the same budget? Does it just take a while for the reach to even out? Or has Facebook decided one version is worth showing more than the other? If it helps, I’m running this test as two duplicate ads, changing only the cover image, rather than as an A/B split test. Is there a better way to do this so both ads get roughly the same amount of impressions?