As @Sirrian had mentioned, during our 2.1.5 Update, we updated the AI only on console. To explain how it changed, check out this post which breaks down how the AI system works on console compared to pre 2.1.5, and how it differs from the current PC/Mobile version of the game.
Update 2.1.5 also introduced the Defense Gem Sliders, which allow players to customize their AI according to what they thought would fit well with their Defense Team. This could explain why the AI decided to avoid the skull match, as your opponent may have changed their sliders to either favor the color that it selected, or pulled down the skull preference to stop players from skull baiting.
As Sirrian had mentioned, if any of the team has mentioned that the AI is the same on Console and PC/Mobile (since Infinity Plus Two took over Console development), then we do apologize.